CN116191362A - Control method of power converter and LLC controller - Google Patents

Abstract

Translated fromChinese

本发明实施例提供一种适用一电源转换器的控制方法。该电源转换器包含有一上臂开关以及一下臂开关，电性串接于一输入电源以及一接地线之间，来驱动一谐振电路。该电源转换器另包含有一检测电路，检测该谐振电路，来提供一检测信号。该控制方法包含有：提供一上臂控制信号以及一下臂控制信号，来分别控制该上臂开关与该下臂开关；检测该上臂开关与该下臂开关其中之一的一工作周期；依据该工作周期，提供一临界值；以及，依据该检测信号以及该临界值，来触发一过电流保护。该过电流保护被触发时，该上臂控制信号以及该下臂控制信号使该谐振电路停止震荡。

An embodiment of the present invention provides a control method applicable to a power converter. The power converter includes an upper arm switch and a lower arm switch, electrically connected in series between an input power supply and a ground wire to drive a resonant circuit. The power converter further includes a detection circuit for detecting the resonant circuit to provide a detection signal. The control method includes: providing an upper arm control signal and a lower arm control signal to respectively control the upper arm switch and the lower arm switch; detecting a duty cycle of one of the upper arm switch and the lower arm switch; according to the duty cycle , providing a critical value; and triggering an overcurrent protection according to the detection signal and the critical value. When the overcurrent protection is triggered, the upper arm control signal and the lower arm control signal stop the resonant circuit from oscillating.

Description

Translated fromChinese

电源转换器的控制方法以及LLC控制器Control method of power converter and LLC controller

技术领域technical field

本发明大致是关于一种开关式电源转换器的控制方法以及相关的控制器，尤指可以适用于LLC谐振电源转换器的过电流保护的控制方法与相关的控制器。The present invention generally relates to a control method of a switching power converter and a related controller, especially a control method and a related controller suitable for overcurrent protection of an LLC resonant power converter.

背景技术Background technique

LLC谐振电源转换器为一种转换效率相当优异的开关式电源供应器。开关式电源供应器中，功率开关往往是消耗功率的主要元件之一。理论上，LLC谐振电源转换器的每个开关周期，都可以使两个最主要的功率开关，也就是上臂开关与下臂开关，进行零电压切换(zero voltage switching，ZVS)。因此，上臂开关与下臂开关的导通损失(conductionloss)就可以控制在非常低的程度。LLC谐振电源转换器大多适用于大功率的电源供应器。The LLC resonant power converter is a switching power supply with excellent conversion efficiency. In a switching power supply, the power switch is often one of the main components that consume power. Theoretically, each switching cycle of the LLC resonant power converter can make the two most important power switches, that is, the upper arm switch and the lower arm switch, perform zero voltage switching (ZVS). Therefore, the conduction loss between the upper arm switch and the lower arm switch can be controlled to a very low level. LLC resonant power converters are mostly suitable for high-power power supplies.

单一输出的LLC谐振电源转换器，一般是采用对称式(symmetric)脉波宽度调制(pulse width modulation，PWM)。双输出(dual-output)的LLC谐振电源转换器可以采用非对称式脉波宽度调制(asymmetric PWM，APWM)，来实现对输出电压的准确控制(tightoutput voltage regulation)。只是，如何在APWM的控制下，可以实现对输出电流准确控制，来实现一些一般电源供应器所必需的过电流保护(over current protection)或是过负载保护(over load protection)，是业界持续努力的目标。A single-output LLC resonant power converter generally adopts symmetric pulse width modulation (PWM). A dual-output (dual-output) LLC resonant power converter can use asymmetric pulse width modulation (asymmetric PWM, APWM) to achieve accurate control of the output voltage (tight output voltage regulation). However, how to accurately control the output current under the control of APWM to realize the over current protection (over current protection) or overload protection (over load protection) necessary for some general power supplies is a continuous effort in the industry. The goal.

发明内容Contents of the invention

本发明实施例提供一种适用一电源转换器的控制方法。该电源转换器包含有一上臂开关以及一下臂开关，电性串接于一输入电源以及一接地线之间，来驱动一谐振电路。该电源转换器另包含有一检测电路，检测该谐振电路，来提供一检测信号。该控制方法包含有：提供一上臂控制信号以及一下臂控制信号，来分别控制该上臂开关与该下臂开关；检测该上臂开关与该下臂开关其中之一的一工作周期；依据该工作周期，提供一临界值；以及，依据该检测信号以及该临界值，来触发一过电流保护。该过电流保护被触发时，该上臂控制信号以及该下臂控制信号使该谐振电路停止震荡。An embodiment of the present invention provides a control method applicable to a power converter. The power converter includes an upper arm switch and a lower arm switch, electrically connected in series between an input power supply and a ground wire to drive a resonant circuit. The power converter further includes a detection circuit for detecting the resonant circuit to provide a detection signal. The control method includes: providing an upper arm control signal and a lower arm control signal to respectively control the upper arm switch and the lower arm switch; detecting a duty cycle of one of the upper arm switch and the lower arm switch; according to the duty cycle , providing a critical value; and triggering an overcurrent protection according to the detection signal and the critical value. When the overcurrent protection is triggered, the upper arm control signal and the lower arm control signal stop the resonant circuit from oscillating.

本发明实施例提供一LLC控制器，适用于一LLC谐振电源转换器。该LLC谐振电源转换器包含有一谐振电路、一上臂开关以及一下臂开关、以及一检测电路。该上臂开关以及该下臂开关，电性串接于一输入电源以及一接地线之间，来驱动该谐振电路，以维持该谐振电路震荡。该检测电路电性连接至该谐振电路，来提供一检测信号。该LLC控制器控制该上臂开关以及该下臂开关。该LLC控制器包含有一工作周期检测器、一临界值生成器、以及一过电流保护器。该工作周期检测器检测该上臂开关以及该下臂开关其中之一的一工作周期。该临界值生成器依据该工作周期，提供一临界值。该过电流保护器依据该临界值以及该检测信号，来触发一过电流保护。当该过电流保护被触发时，该上臂开关与该下臂开关被控制来使得该谐振电路停止震荡。An embodiment of the present invention provides an LLC controller suitable for an LLC resonant power converter. The LLC resonant power converter includes a resonant circuit, an upper arm switch, a lower arm switch, and a detection circuit. The upper arm switch and the lower arm switch are electrically connected in series between an input power supply and a ground wire to drive the resonant circuit and maintain the resonant circuit to oscillate. The detection circuit is electrically connected to the resonant circuit to provide a detection signal. The LLC controller controls the upper arm switch as well as the lower arm switch. The LLC controller includes a duty cycle detector, a threshold generator, and an overcurrent protector. The duty cycle detector detects a duty cycle of one of the upper arm switch and the lower arm switch. The threshold generator provides a threshold according to the duty cycle. The overcurrent protector triggers an overcurrent protection according to the critical value and the detection signal. When the over-current protection is triggered, the upper arm switch and the lower arm switch are controlled to stop the resonant circuit from oscillating.

附图说明Description of drawings

图1为依据本发明所实施的双输出LLC谐振电源转换器100。FIG. 1 shows a dual output LLCresonant power converter 100 according to the present invention.

图2显示依据本发明所实施的LLC控制器102。FIG. 2 shows anLLC controller 102 implemented in accordance with the present invention.

图3A显示工作信号DT_H与临界值V_CSP-OCP之间的关系。FIG. 3A shows the relationship between the operating signal_DTH and the threshold V_CSP-OCP .

图3B显示工作信号DT_H与临界值V_CSP-OCP之间的关系。FIG. 3B shows the relationship between the operating signal_DTH and the threshold V_CSP-OCP .

图4显示当上臂开关HS与下臂开关LS的工作周期大约都是50％时，图1与图2一些信号波形。FIG. 4 shows some signal waveforms in FIG. 1 and FIG. 2 when the duty cycles of the upper arm switch HS and the lower arm switch LS are about 50%.

图5显示当上臂开关HS的工作周期是25％时，图1与图2一些信号波形。Fig. 5 shows some signal waveforms of Fig. 1 and Fig. 2 when the duty cycle of the upper arm switch HS is 25%.

图6显示使用于图1中的LLC谐振电源转换器100内的控制方法M01。FIG. 6 shows a control method M01 used in the LLCresonant power converter 100 in FIG. 1 .

100 LLC谐振电源转换器100 LLC resonant power converter

102 LLC控制器102 LLC Controller

108 检测电路108 detection circuit

202 工作周期检测器202 duty cycle detector

204P、204N 临界值生成器204P, 204N Threshold Generator

206 过电流保护器206 overcurrent protector

208 开启时间控制器208 Open time controller

1041、1042 负载1041, 1042 load

1061、1062 反馈电路1061, 1062 feedback circuit

CA、CB 电容CA, CB capacitance

CL 电容CL capacitance

CO1、CO2 输出电容CO1, CO2 output capacitance

D1、D2 二极管D1, D2 Diodes

DT_H、DT_L 工作信号DT_H ,_DTL working signal

GND_IN 接地线GND_IN ground wire

HS 上臂开关HS upper arm switch

I_CL 电流I_CL current

I_D1、I_D2 感应电流I_D1 , I_D2 induction current

Lm、Lr 电感Lm, Lr inductance

LP 主绕组LP main winding

LS 下臂开关LS lower arm switch

LS1、LS2 二次侧绕组LS1, LS2 secondary side winding

M01 控制方法M01 control method

ND 连接点ND connection point

RA、RB 电阻RA, RB resistors

RSNT 谐振电路RSNT resonant circuit

S10、S12、S14、S16、S18 步骤S10, S12, S14, S16, S18 steps

S_H 上臂控制信号S_H upper arm control signal

S_L 下臂控制信号S_L lower arm control signal

S_OCP 保护信号S_OCP protection signal

TF 变压器TF Transformer

V_CS 电流检测信号V_CS current sense signal

V_CSN-OCP、V_CSP-OCP 临界值V_CSN-OCP , V_CSP-OCP critical value

V_CSP-H、V_CSP-L、V_CSN-H、V_CSN-L 固定常数值V_CSP-H , V_CSP-L , V_CSN-H , V_CSN-L fixed constant values

V_FB1、V_FB2 反馈信号V_FB1 , V_FB2 feedback signal

V_IN 输入电源V_IN input power supply

V_O1、V_O2 输出电源V_O1 , V_O2 output power supply

具体实施方式Detailed ways

在本说明书中，有一些相同的符号，其表示具有相同或是类似之结构、功能、原理的元件，且为业界具有一般知识能力者可以依据本说明书之教导而推知。为说明书之简洁度考量，相同之符号的元件将不再重述。In this specification, there are some same symbols, which represent elements with the same or similar structure, function, and principle, and can be inferred by those with general knowledge in the industry based on the teaching of this specification. For the sake of brevity in the description, elements with the same symbols will not be repeated.

本发明虽然以APWM的双输出LLC谐振电源转换器为例，但本发明并不限于此。在其他实施例中，本发明也可以使用任何其他类型的谐振电源转换器。Although the present invention takes an APWM dual-output LLC resonant power converter as an example, the present invention is not limited thereto. In other embodiments, any other type of resonant power converter may also be used with the present invention.

在本发明的一实施例中，一双输出LLC谐振电源转换器中的一LLC控制器提供两个临界值，来分别判断两个输出是否发生过电流事件，而这两个临界值可以依据驱动一谐振电路的一个功率开关之工作周期而改变，可以避免过电流保护被误触发。In an embodiment of the present invention, an LLC controller in a dual-output LLC resonant power converter provides two critical values to respectively determine whether an over-current event occurs in the two outputs, and the two critical values can be determined according to driving a The duty cycle of a power switch of the resonant circuit is changed, which can avoid false triggering of the over-current protection.

图1为依据本发明所实施的双输出LLC谐振电源转换器100。LLC谐振电源转换器100将输入电源V_IN，转换为输出电源V_O1与V_O2，分别对负载1041与1042供电。FIG. 1 shows a dual output LLCresonant power converter 100 according to the present invention. The LLCresonant power converter 100 converts the input power V_IN into output powers V_O1 and V_O2 to supply power to theloads 1041 and 1042 respectively.

上臂开关HS与下臂开关LS电性串接于输入电源V_IN与接地线GND_IN之间，用来驱动谐振电路RSNT，使谐振电路RSNT震荡。谐振电路RSNT包含有变压器TF与电容CL。变压器TF中的主绕组LP与两个二次侧绕组LS1与LS2相互电感耦合。变压器TF中的电感Lr与Lm表示变压器TF的主绕组LP的串接漏感与并联漏感。主绕组LP与电容CL通过连接点ND相串联。在其他实施例中，谐振电路RSNT可以有不同的架构，并不限于图1中的结构。The upper arm switch HS and the lower arm switch LS are electrically connected in series between the input power V_IN and the ground line GND_IN for driving the resonant circuit RSNT to make the resonant circuit RSNT oscillate. The resonant circuit RSNT includes a transformer TF and a capacitor CL. The primary winding LP in the transformer TF is inductively coupled to the two secondary windings LS1 and LS2. The inductance Lr and Lm in the transformer TF represent the series leakage inductance and the parallel leakage inductance of the main winding LP of the transformer TF. The main winding LP is connected in series with the capacitor CL through the connection point ND. In other embodiments, the resonant circuit RSNT may have different structures, and is not limited to the structure shown in FIG. 1 .

谐振电路RSNT震荡时，二次侧绕组LS1与LS2会生成感应电流I_D1与I_D2，通过二极管D1与D2的整流，可以在输出电容CO1与CO2上建立起输出电源V_O1与V_O2。When the resonant circuit RSNT oscillates, the secondary side windings LS1 and LS2 will generate induced currents_ID1 and I_D2 , which can be rectified by the diodes D1 and D2 to establish output power supplies V_O1 and V_O2 on the output capacitors CO1 and CO2.

输出电源V_O1与V_O2可以通过反馈电路1061与1062，分别生成反馈信号V_FB1与V_FB2。LLC控制器102提供上臂控制信号S_H与下臂控制信号S_L，分别控制上臂开关HS与下臂开关LS。依据反馈信号V_FB1与V_FB2，LLC控制器102可以决定上臂开关HS与下臂开关LS的开启时间(ONtime)，也就是导通时间。The output power supplies V_O1 and V_O2 can generate feedback signals V_FB1 and V_FB2 respectively through thefeedback circuits 1061 and 1062 . TheLLC controller 102 provides an upper arm control signal_SH and a lower arm control signal_SL to control the upper arm switch HS and the lower arm switch LS respectively. According to the feedback signals V_FB1 and V_FB2 , theLLC controller 102 can determine the ON time (ON time) of the upper arm switch HS and the lower arm switch LS, that is, the conduction time.

LLC谐振电源转换器100包含有检测电路108，由电阻RA、RB以及电容CA与CB所构成，彼此连接如同图1举例所示。检测电路108连接到连接点ND，用来检测谐振电路RSNT中跨于电容CL上的电压，具以生成电流检测信号V_CS。电流检测信号V_CS只是检测信号的一种，其他实施例中，检测电路108可以提供不同于电流检测信号V_CS的检测信号。The LLCresonant power converter 100 includes adetection circuit 108 composed of resistors RA, RB and capacitors CA and CB, which are connected to each other as shown in FIG. 1 for example. Thedetection circuit 108 is connected to the connection point ND for detecting the voltage across the capacitor CL in the resonant circuit RSNT to generate a current detection signal V_CS . The current detection signal V_CS is only one type of detection signal, and in other embodiments, thedetection circuit 108 may provide a detection signal different from the current detection signal V_CS .

图2显示依据本发明所实施的LLC控制器102，包含有开启时间控制器208、工作周期检测器202、临界值生成器204P与204N、以及过电流保护器206。FIG. 2 shows theLLC controller 102 implemented in accordance with the present invention, including an on-time controller 208 , aduty cycle detector 202 ,threshold generators 204P and 204N, and anovercurrent protector 206 .

开启时间控制器208依据反馈信号V_FB1与V_FB2，生成上臂控制信号S_H与下臂控制信号S_L，分别控制上臂开关HS与下臂开关LS，也决定了上臂开关HS与下臂开关LS的开启时间。开启时间控制器208也架构来使得上臂开关HS与下臂开关LS实现零电压切换(zerovoltage switching，ZVS)，也就是大约在一开关的一通道跨压约为0V时，开启该开关，可以减少开关损失。The turn-on time controller 208 generates the upper arm control signal_SH and the lower arm control signal S L according to the feedback signals V_FB1 and V_FB2 , respectively controls the upper arm switch HS and the lower arm switch_LS , and also determines the upper arm switch HS and the lower arm switch LS. of the opening time. The turn-on time controller 208 is also configured to enable the upper arm switch HS and the lower arm switch LS to realize zero voltage switching (ZVS), that is, when the cross voltage of a channel of a switch is about 0V, the switch is turned on, which can reduce switching loss.

在图2中，工作周期检测器202依据上臂控制信号S_H，提供工作信号DT_H，代表上臂开关HS的工作周期。工作信号DT_H可以代表0％到100％中的一数值。工作信号DT_L代表下臂开关LS的工作周期，可以通过工作信号DT_H类推得知，因为工作信号DT_L与工作信号DT_H彼此互补，相加大约为1。举例来说，当工作信号DT_H为35％(代表上臂开关HS的工作周期为35％)时，互补的工作信号DT_L(代表上臂开关HS的工作周期)是65％。在另一实施例中，工作周期检测器202可以依据下臂控制信号S_L，来生成并提供工作信号DT_L，而工作信号DT_H可以类推得知。In FIG. 2 , theduty cycle detector 202 provides a duty signal_DTH representing the duty cycle of the upper arm switch_HS according to the upper arm control signal SH . The working signal_DTH can represent a value from 0% to 100%. The working signal_DTL represents the working period of the lower arm switch LS, which can be obtained by analogy from the working signal DT_H , because the working signal_DTL and the working signal DT_H are complementary to each other, and the sum of them is about 1. For example, when the working signal_DTH is 35% (representing the duty cycle of the upper arm switch HS is 35%), the complementary operating signal_DTL (representing the duty cycle of the upper arm switch HS) is 65%. In another embodiment, theduty cycle detector 202 can generate and provide the duty signal_DTL according to the lower arm control signal S_L , and the duty signal_DTH can be obtained by analogy.

图2中，临界值生成器204P与204N依据工作信号DT_H，分别提供临界值V_CSP-OCP与临界值V_CSN-OCP。在某些状态中，工作信号DT_H的变化，会导致临界值V_CSP-OCP或临界值V_CSN-OCP的改变。图3A显示工作信号DT_H与临界值V_CSP-OCP之间的关系。当工作信号DT_H大于35％时，临界值V_CSP-OCP大约为不随工作信号DT_H改变的固定常数值V_CSP-L；当工作信号DT_H小于15％时，临界值V_CSP-OCP大约为不随工作信号DT_H改变的固定常数值V_CSP-H；当工作信号DT_H介于15％与35％之间时，临界值V_CSP-OCP随着工作信号DT_H的变化而线性的改变。类似的，图3B显示工作信号DT_H与临界值V_CSN-OCP之间的关系。当工作信号DT_H介于65％与85％之间时，临界值V_CSN-OCP随着工作信号DT_H的变化而线性的改变。在工作信号DT_H小于65％或大于85％时，临界值V_CSN-OCP分别是不随工作信号DT_H改变的固定常数值V_CSN-L与固定常数值V_CSN-H，如同图3B所示。在一实施例中，四个固定常数值V_CSP-H、V_CSP-L、V_CSN-H、V_CSN-L都为正值。In FIG. 2 , thethreshold generators 204P and 204N respectively provide the threshold V_CSP-OCP and the threshold V_CSN-OCP according to the working signal_DTH . In some states, the change of the working signal_DTH will cause the change of the threshold V_CSP-OCP or the threshold V_CSN-OCP . FIG. 3A shows the relationship between the operating signal_DTH and the threshold V_CSP-OCP . When the working signal DT_H is greater than 35%, the critical value V_CSP-OCP is about a fixed constant value V_CSP-L that does not change with the working signal DT_H ; when the working signal DT_H is less than 15%, the critical value V_CSP-OCP is about It is a fixed constant value V_CSP-H that does not change with the working signal DT_H ; when the working signal DT_H is between 15% and 35%, the critical value V_CSP-OCP changes linearly with the change of the working signal DT_H . Similarly, FIG. 3B shows the relationship between the operating signal_DTH and the threshold V_CSN-OCP . When the working signal_DTH is between 65% and 85%, the critical value V_CSN-OCP changes linearly with the change of the working signal_DTH . When the operating signal DT_H is less than 65% or greater than 85%, the critical value V_CSN-OCP is a fixed constant value V_CSN-L and a fixed constant value V_CSN-H that do not change with the operating signal DT_H , as shown in Figure 3B . In one embodiment, the four fixed constants V_CSP-H , V_CSP-L , V_CSN-H , V_CSN-L are all positive values.

图4显示当上臂开关HS与下臂开关LS的工作周期大约都是50％时，图1与图2一些信号波形。从上到下，图4中的信号波形分别是上臂控制信号S_H、下臂控制信号S_L、流过电容CL的电流I_CL、电流检测信号V_CS、在二次侧分别流过二极管D1与D2的感应电流I_D1与I_D2。举例来说，图4的信号波形可能发生在图1中的负载1041与1042均为中载的情形。FIG. 4 shows some signal waveforms in FIG. 1 and FIG. 2 when the duty cycles of the upper arm switch HS and the lower arm switch LS are about 50%. From top to bottom, the signal waveforms in Figure 4 are the upper arm control signal_SH , the lower arm control signal S_L , the current I_CL flowing through the capacitor CL, the current detection signal V_CS , and the diode D1 flowing through the secondary side respectively. and D2 sense currents I_D1 and I_D2 . For example, the signal waveform in FIG. 4 may occur when theloads 1041 and 1042 in FIG. 1 are both medium loads.

如果忽略上臂开关HS与下臂开关LS都为关闭时的空载时间(dead time)，从图4的上臂控制信号S_H与下臂控制信号S_L可知，当下图4中的上臂开关HS与下臂开关LS的工作周期大约都是50％，也就是工作信号DT_H为50％。根据图3A与3B，图4中的临界值V_CSP-OCP与V_CSN-OCP会分别为固定常数值VCSH-L与VCSL-L。If ignoring the dead time when both the upper arm switch HS and the lower arm switch LS are closed, it can be known from the upper arm control signal_SH and the lower arm control signal S_L in FIG. 4 that the upper arm switch HS and the lower arm switch LS in FIG. The duty cycle of the lower arm switch LS is about 50%, that is, the duty signal DT_H is 50%. According to FIGS. 3A and 3B , the critical values V_CSP-OCP and V_CSN-OCP in FIG. 4 are fixed constant values VCSH-L and VCSL-L, respectively.

请参阅图2与图4。图2中过电流保护器206依据临界值V_CSP-OCP与临界值V_CSN-OCP，以及从检测电路108所提供的电流检测信号V_CS，来决定是否输出电源V_O1与V_O2其中之一发生过电流事件，来触发过电流保护(over current protection，OCP)。Please refer to Figure 2 and Figure 4. In FIG. 2 , theovercurrent protector 206 determines whether to output one of the power supplies V_O1 and V_O2 according to the critical value V_CSP-OCP and the critical value V_CSN-OCP , and the current detection signal V_CS provided by thedetection circuit 108. An overcurrent event occurs to trigger overcurrent protection (over current protection, OCP).

举例来说，如果过电流保护器206发现电流检测信号V_CS超过了临界值V_CSP-OCP，且发生次数达一定的连续次数，过电流保护器206就认定输出电源V_O1发生了过电流事件，触发OCP。类似的，如果过电流保护器206发现电流检测信号V_CS低于临界值-V_CSN-OCP，且发生次数达一定的连续次数，过电流保护器206就认定输出电源V_O2发生了过电流事件，触发OCP。For example, if theovercurrent protector 206 finds that the current detection signal V_CS exceeds the critical value V_CSP-OCP and the number of occurrences reaches a certain continuous number of times, theovercurrent protector 206 will determine that an overcurrent event has occurred in the output power supply V_O1 , trigger OCP. Similarly, if theovercurrent protector 206 finds that the current detection signal V_CS is lower than the critical value -V_CSN-OCP , and the number of occurrences reaches a certain continuous number of times, theovercurrent protector 206 will determine that an overcurrent event has occurred in the output power supply V_O2 , trigger OCP.

图4显示当下电流检测信号V_CS变化于临界值V_CSP-OCP与-V_CSN-OCP所界定地容许范围内。因此，在图4的信号波形中，过电流保护器206不会触发OCP。FIG. 4 shows that the variation of the current detection signal V_CS is within the allowable range defined by the critical values V_CSP-OCP and -V_CSN-OCP . Therefore, in the signal waveform of FIG. 4 , the OCP will not be triggered by theovercurrent protector 206 .

当OCP触发时，过电流保护器206认定过电流事件发生，通过保护信号S_OCP，过电流保护器206禁能开启时间控制器208，控制上臂开关HS与下臂开关LS，使得谐振电路RSNT随着能量的损耗而停止震荡。如此，谐振电源转换器100停止供应电能给输出电源V_O1与V_O2。只要上臂开关HS与下臂开关LS任何一个维持关闭(不导通)，谐振电路RSNT的震荡就会渐渐停止。举例来说，在一实施例中，当OCP被触发时，过电流保护器206使得上臂开关HS与下臂开关LS都持续保持关闭的状态。在另一个实施例中，当OCP被触发时，上臂开关HS与下臂开关LS其中之一保持关闭，而另一保持开启。When the OCP is triggered, theovercurrent protector 206 determines that an overcurrent event has occurred, and through the protection signal S_OCP , theovercurrent protector 206 disables the time controller 208 and controls the upper arm switch HS and the lower arm switch LS, so that the resonant circuit RSNT follows Oscillation stops with loss of energy. In this way, theresonant power converter 100 stops supplying power to the output power sources V_O1 and V_O2 . As long as any one of the upper arm switch HS and the lower arm switch LS remains closed (non-conductive), the oscillation of the resonant circuit RSNT will gradually stop. For example, in one embodiment, when the OCP is triggered, theovercurrent protector 206 keeps both the upper arm switch HS and the lower arm switch LS in an off state. In another embodiment, when the OCP is triggered, one of the upper arm switch HS and the lower arm switch LS remains closed, while the other remains open.

图5显示当上臂开关HS的工作周期(工作信号DT_H)是25％时，图1与图2一些信号波形。工作信号DT_H是25％，同时意味了下臂开关LS的工作周期(工作信号DT_L)为75％。举例来说，图5的信号波形可能发生在图1中的负载1041为中载，而负载1042为轻载的情形。根据图3A中所显示的工作信号DT_H与临界值V_CSP-OCP之间的关系，因为上臂开关HS的工作周期是25％，所以图5中的临界值V_CSP-OCP大约为固定常数值V_CSP-H与固定常数值V_CSP-L的中间值。图5中，电流检测信号V_CS依然位于临界值V_CSP-OCP与-V_CSN-OCP所界定的容许范围之内，因此，过电流保护器206也不会触发OCP。FIG. 5 shows some signal waveforms in FIG. 1 and FIG. 2 when the duty cycle of the upper arm switch HS (the duty signal_DTH ) is 25%. The duty signal DT_H is 25%, which means that the duty cycle of the lower arm switch LS (the duty signal_DTL ) is 75%. For example, the signal waveform in FIG. 5 may occur when the load 1041 in FIG. 1 is a medium load and theload 1042 is a light load. According to the relationship between the working signal DT_H and the critical value V_CSP-OCP shown in Fig. 3A, because the duty cycle of the upper arm switch HS is 25%, the critical value V_CSP-OCP in Fig. 5 is approximately a fixed constant value Intermediate value between V_CSP-H and fixed constant value V_CSP-L . In FIG. 5 , the current detection signal V_CS is still within the allowable range defined by the critical values V_CSP-OCP and -V_CSN-OCP , therefore, theover-current protector 206 will not trigger the OCP.

假设图5中的临界值V_CSP-OCP还是如同图4一样，还是为固定常数值V_CSP-L。那明显的，尽管此时图1中的负载1041为中载，没有过电流事件发生，但输出电源V_O1将会被误认为发生了过电流事件，OCP将会被触发，因为电流检测信号V_CS的峰值确实超过了固定常数值V_CSP-L，如同图5所显示的。换言之，依据图3A，当工作信号DT_H(上臂开关HS的工作周期)少于35％时，增加临界值V_CSP-OCP，可以预防误认输出电源V_O1发生了过电流事件。类似的，依据图3B，当工作信号DT_H大于65％时，增加临界值V_CSN-OCP，可以预防误认输出电源V_O2发生了过电流事件。Assume that the critical value V_CSP-OCP in FIG. 5 is still the same as that in FIG. 4 , and is still a fixed constant value V_CSP-L . Obviously, even though the load 1041 in Fig. 1 is medium load at this time and no over-current event occurs, the output power V_O1 will be mistaken for an over-current event, and the OCP will be triggered, because the current detection signal V The peak value of_CS does exceed the fixed constant value V_CSP-L , as shown in FIG. 5 . In other words, according to FIG. 3A , when the operating signal_DTH (the duty cycle of the upper arm switch HS) is less than 35%, increasing the threshold V_CSP-OCP can prevent misidentification of an overcurrent event occurring in the output power V_O1 . Similarly, according to FIG. 3B , when the working signal DT_H is greater than 65%, increasing the threshold V_CSN-OCP can prevent misidentification that an overcurrent event has occurred in the output power V_O2 .

简单的说，临界值V_CSP-OCP与-V_CSN-OCP可以界定一容许范围，作为容许范围的两边界。过电流保护器206依据这容许范围以及电流检测信号V_CS来触发OCP。从图3A与3B可以发现，当工作信号DT_H介于35％到65％的中间区域时，临界值V_CSP-OCP与-V_CSN-OCP都是不随工作周期变化的固定值，所以容许范围是一标准范围，从固定常数值-V_CSN-L到V_CSP-L。当工作信号DT_H小于35％，位于中间区域之外后，临界值V_CSP-OCP随着工作信号DT_H减少而增加，这容许范围转变为一相对宽范围，含盖了标准范围。当工作信号DT_H大于65％，位于中间区域之外后，临界值V_CSN-OCP随着工作信号DT_H增加而增加，这容许范围转变为另一相对宽范围，也含盖了标准范围。In short, the critical values V_CSP-OCP and -V_CSN-OCP can define an allowable range as two boundaries of the allowable range. Theover-current protector 206 triggers the OCP according to the allowable range and the current detection signal V_CS . From Figures 3A and 3B, it can be found that when the operating signal DT_H is in the middle region of 35% to 65%, the critical values V_CSP-OCP and -V_CSN-OCP are fixed values that do not change with the duty cycle, so the allowable range is a standard range from a fixed constant value -V_CSN-L to V_CSP-L . When the operating signal DT_H is less than 35% and outside the middle region, the critical value V_CSP-OCP increases as the operating signal DT_H decreases, and the allowable range turns into a relatively wide range, covering the standard range. When the operating signal DT_H is greater than 65% and is outside the middle region, the critical value V_CSN-OCP increases as the operating signal DT_H increases, and the allowable range changes to another relatively wide range, which also covers the standard range.

图6显示使用于图1中的LLC谐振电源转换器100内的控制方法M01。请同时参阅图1、图2与图6。在步骤S10，上臂控制信号S_H与下臂控制信号S_L，分别控制上臂开关HS与下臂开关LS。在步骤S12，工作周期检测器202依据上臂控制信号S_H，提供工作信号DT_H，代表上臂开关HS的工作周期。在步骤S14，临界值生成器204P与204N依据工作信号DT_H，分别提供临界值V_CSP-OCP与临界值V_CSN-OCP。在步骤S16，检测电路108检测谐振电路RSNT，具以生成电流检测信号V_CS。在步骤S18，过电流保护器206依据临界值V_CSP-OCP与临界值V_CSN-OCP，以及从检测电路108所提供的电流检测信号V_CS，来检测发生过电流事件，并触发过电流保护。FIG. 6 shows a control method M01 used in the LLCresonant power converter 100 in FIG. 1 . Please refer to Figure 1, Figure 2 and Figure 6 together. In step S10, the upper arm control signal_SH and the lower arm control signal S_L respectively control the upper arm switch HS and the lower arm switch LS. In step S12, theduty cycle detector 202 provides a duty signal_DTH representing the duty cycle of the upper arm switch_HS according to the upper arm control signal SH. In step S14 , thethreshold generators 204P and 204N respectively provide the threshold V_CSP-OCP and the threshold V_CSN-OCP according to the operation signal_DTH . In step S16, thedetection circuit 108 detects the resonant circuit RSNT to generate a current detection signal V_CS . In step S18, theovercurrent protector 206 detects the occurrence of an overcurrent event according to the critical value V_CSP-OCP and the critical value V_CSN-OCP and the current detection signal V_CS provided by thedetection circuit 108, and triggers the overcurrent protection .

以上所述仅为本发明之较佳实施例，凡依本发明申请专利范围所做之均等变化与修饰，皆应属本发明之涵盖范围。The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims (10)

Translated fromChinese

1.一种适用一电源转换器的控制方法，该电源转换器包含有一上臂开关以及一下臂开关，电性串接于一输入电源以及一接地线之间，来驱动一谐振电路(resonant circuit)，使该谐振电路震荡，该电源转换器另包含有一检测电路，检测该谐振电路，来提供一检测信号，该控制方法包含有：1. A control method suitable for a power converter, the power converter includes an upper arm switch and a lower arm switch, electrically connected in series between an input power supply and a grounding line, to drive a resonant circuit (resonant circuit) , to make the resonant circuit oscillate, the power converter further includes a detection circuit for detecting the resonant circuit to provide a detection signal, the control method includes:提供一上臂控制信号以及一下臂控制信号，来分别控制该上臂开关与该下臂开关；providing an upper arm control signal and a lower arm control signal to respectively control the upper arm switch and the lower arm switch;检测该上臂开关与该下臂开关其中之一的一工作周期；detecting a duty cycle of one of the upper arm switch and the lower arm switch;依据该工作周期，提供一临界值；以及providing a threshold value according to the duty cycle; and依据该检测信号以及该临界值，来触发一过电流保护；triggering an overcurrent protection according to the detection signal and the critical value;其中，该过电流保护被触发时，该上臂控制信号以及该下臂控制信号使该谐振电路停止震荡。Wherein, when the overcurrent protection is triggered, the upper arm control signal and the lower arm control signal stop the resonant circuit from oscillating.2.如权利要求1所述的控制方法，包含有：2. The control method as claimed in claim 1, comprising:依据该工作周期，提供一第一临界值以及一第二临界值，该第一临界值与该第二临界值可用以界定一容许范围；以及According to the duty cycle, a first critical value and a second critical value are provided, and the first critical value and the second critical value can be used to define an allowable range; and依据该容许范围与该检测信号，来触发该过电流保护。The overcurrent protection is triggered according to the allowable range and the detection signal.3.如权利要求2所述的控制方法，其中，当该工作周期为50％时，该容许范围为一标准范围，当该工作周期为小于50％的一相对小工作周期时，该容许范围为一相对宽范围，且该相对宽范围包含了该标准范围。3. The control method according to claim 2, wherein, when the duty cycle is 50%, the allowable range is a standard range, and when the duty cycle is a relatively small duty cycle less than 50%, the allowable range is a relatively wide range, and the relatively wide range includes the standard range.4.如权利要求1所述的控制方法，其中，当该工作周期位于一中间区域之内时，该临界值大约为一定值，不随工作周期变化而改变，该中间区域包含了50％，且当该工作周期位于该中间区域之外时，该临界值随着该工作周期变化而改变。4. The control method as claimed in claim 1, wherein, when the duty cycle is within a middle region, the critical value is about a certain value, which does not change with the change of the duty cycle, and the middle region includes 50%, and When the duty cycle is outside the intermediate region, the threshold value changes as the duty cycle changes.5.如权利要求1所述的控制方法，其中，该谐振电路包含有一变压器以及一电容，该变压器具有一主绕组，通过一连接端，与该电容以及该检测电路相电连接。5. The control method according to claim 1, wherein the resonant circuit comprises a transformer and a capacitor, the transformer has a main winding, and is electrically connected to the capacitor and the detection circuit through a connecting terminal.6.一种LLC控制器，适用于一LLC谐振电源转换器(LLC resonant converter)，该LLC谐振电源转换器包含有：6. An LLC controller, suitable for an LLC resonant power converter (LLC resonant converter), the LLC resonant power converter includes:一谐振电路(resonant circuit)；a resonant circuit;一上臂开关以及一下臂开关，电性串接于一输入电源以及一接地线之间，来驱动该谐振电路，以维持该谐振电路震荡；以及an upper arm switch and a lower arm switch, electrically connected in series between an input power supply and a grounding line, to drive the resonant circuit to maintain the resonant circuit to oscillate; and一检测电路，电性连接至该谐振电路，来提供一检测信号；a detection circuit electrically connected to the resonant circuit to provide a detection signal;该LLC控制器控制该上臂开关以及该下臂开关，该LLC控制器包含有：The LLC controller controls the upper arm switch and the lower arm switch, and the LLC controller includes:一工作周期检测器，检测该上臂开关以及该下臂开关其中之一的一工作周期；a duty cycle detector for detecting a duty cycle of one of the upper arm switch and the lower arm switch;一临界值生成器，依据该工作周期，提供一临界值；以及a threshold generator, which provides a threshold according to the duty cycle; and一过电流保护器，依据该临界值以及该检测信号，来触发一过电流保护；an overcurrent protector, triggering an overcurrent protection according to the critical value and the detection signal;其中，当该过电流保护被触发时，该上臂开关与该下臂开关被控制来使得该谐振电路停止震荡。Wherein, when the overcurrent protection is triggered, the upper arm switch and the lower arm switch are controlled to make the resonant circuit stop oscillating.7.如权利要求1所述的LLC控制器，其中，该谐振电路包含有一电容以及一变压器之一主绕组，该检测电路通过一连接端，与该电容以及该主绕组相电连接。7. The LLC controller as claimed in claim 1, wherein the resonant circuit comprises a capacitor and a main winding of a transformer, and the detection circuit is electrically connected to the capacitor and the main winding through a connecting terminal.8.如权利要求1所述的LLC控制器，其中，该临界值生成器依据该工作周期，提供一第一临界值以及一第二临界值，以及该过电流保护器依据该第一临界值、该第二临界值与该检测信号，来触发该过电流保护。8. The LLC controller as claimed in claim 1, wherein the threshold generator provides a first threshold and a second threshold according to the duty cycle, and the overcurrent protector provides a threshold value according to the first threshold , the second critical value and the detection signal to trigger the overcurrent protection.9.如权利要求8所述的LLC控制器，其中，该第一临界值与该第二临界值可定义一容许范围，当该工作周期为50％时，该容许范围为一标准范围，当该工作周期为小于50％的一相对小工作周期时，该容许范围为一相对宽范围，且该相对宽范围包含了该标准范围。9. The LLC controller as claimed in claim 8, wherein the first critical value and the second critical value can define an allowable range, and when the duty cycle is 50%, the allowable range is a standard range, when When the duty cycle is a relatively small duty cycle less than 50%, the allowable range is a relatively wide range, and the relatively wide range includes the standard range.10.如权利要求6所述的LLC控制器，其中，当该工作周期位于一中间区域之内时，该临界值大约为一定值，不随工作周期变化而改变，该中间范围包含了50％，且当该工作周期位于该中间范围之外之一外部区域时，该临界值随着该工作周期变化而改变。10. The LLC controller as claimed in claim 6, wherein, when the duty cycle is within a middle range, the critical value is about a certain value, which does not change with the duty cycle, and the middle range includes 50%, And when the duty cycle is in an outer region outside the middle range, the critical value changes as the duty cycle changes.

Images