CN202256445U - Voltage detection circuit - Google Patents

Abstract

A voltage detection circuit comprises a voltage circuit to be detected, a rectifying filter circuit, a switching power supply chip, a switching transformer, a power output circuit and a voltage detection output circuit which are sequentially connected, wherein the switching transformer consists of more than 2 windings and is in a forward working mode, a flyback working mode or a forward and flyback combined working mode. The switching transformer consists of 3 windings, which are T1-2, T6-10 and T8-7 respectively. The winding T1-2 is connected with the switch power supply chip in series and then connected with the rectifying and filtering circuit, and the winding T6-10 is connected with the T8-7 in series and then connected with the power output circuit. A flyback working mode is formed between the windings T1-2 and T6-10, and a forward working mode is formed between the windings T1-2 and T8-7. The winding T6-10 of the switch transformer of the utility model generates induced voltage, which is used for supplying power to other parts of the system after rectification and filtration; the winding T8-7 generates an induced voltage proportional to the input voltage, and the induced voltage is sent to the singlechip AD port after rectification and filtering to calculate the magnitude of the input voltage.

Description

Voltage detecting circuit

Technical field

The utility model relates to a kind of voltage detecting circuit, can be used in the electric equipment that needs to detect input voltage, includes but not limited to the voltage detecting circuit of household electrical appliances, electrical engineering, consumer electronics, automotive electronics.

Background technology

The method of operating of existing detection input voltage is many, and major part all needs the separate voltages testing circuit to accomplish; For example select the Industrial Frequency Transformer circuit, perhaps voltage checking chip.The major defect of existing scheme is: cost is higher, and volume is bigger, does not isolate etc.

The utility model content

The purpose of the utility model aims to provide a kind of dependable performance, voltage detecting circuit with low cost, to overcome weak point of the prior art.

A kind of voltage detecting circuit by this purpose design; Comprise the potential circuit to be measured, current rectifying and wave filtering circuit, switching power source chip, switch transformer, power output circuit and the detection voltage follower circuit that connect successively; It is characterized in that switch transformer is made up of the winding more than 2; It is the positive activation type mode of operation, perhaps inverse-excitation type mode of operation, perhaps positive and negative sharp combined type mode of operation.

Said switch transformer is made up of 3 windings, and it is respectively T1-2, T6-10 and T8-7; Winding T1-2 is connected with current rectifying and wave filtering circuit with switching power source chip serial connection back, and winding T6-10 is connected with power output circuit with T8-7 serial connection back.

Being the inverse-excitation type mode of operation between said winding T1-2 and the T6-10, is the positive activation type mode of operation between winding T1-2 and the T8-7.

Said potential circuit to be measured is the direct current input or exchanges input that the frequency that exchanges input is 50Hz or 60Hz.

Said switching power source chip is a PWM control mode pattern, perhaps is PFC control mode pattern.

Said switching power source chip is the digital control approach pattern, perhaps is the analog control mode pattern.

Said switching power source chip is provided with the extension switch, and it is the integration mode pattern, or discrete device mode pattern.

Said extension switch is a former limit feedback system pattern, perhaps is secondary feedback system pattern.

Said detection voltage follower circuit is connected with the AD mouth of single-chip microcomputer, and/or is connected power supply with other circuit.

When the switching power source chip of the utility model was worked, switch transformer produced induced voltage by the anti-winding T6-10 that swashs theory structure, behind rectifying and wave-filtering, gave other part power supply of system; Winding T8-7 by the normal shock theory structure produces the induced voltage that is directly proportional with input voltage, behind rectifying and wave-filtering, send the Chip Microcomputer A mouth can calculate the size of input voltage.It has simplicity of design, dependable performance, characteristics with low cost.

Description of drawings

Fig. 1 is the circuit diagram of the utility model one embodiment voltage detecting circuit.

Fig. 2 is the theory diagram of an embodiment voltage detecting circuit.

Embodiment

Below in conjunction with accompanying drawing and embodiment the utility model is further described.

Referring to Fig. 1-Fig. 2; This voltage detecting circuit; Comprise potential circuit to be measured 1, current rectifying and wave filtering circuit 2, switching power source chip 3, switch transformer 4, the power output circuit 5 that connects successively and detect voltage follower circuit, its switch transformer 4 is made up of the winding more than 2, and it is the positive activation type mode of operation; Perhaps inverse-excitation type mode of operation, perhaps positive and negative sharp combined type mode of operation.4 level output circuits of switch transformer can be exported the normal shock induced voltage, also can export anti-excitation and answer voltage; Can be used as system power supply, also can be used as input voltage and detect.

The switch transformer 4 of present embodiment is made up of 3 windings, and it is respectively T1-2, T6-10 and T8-7.Winding T1-2 is connected with current rectifying and wave filtering circuit 2 with switching power source chip 3 serial connection backs, and winding T6-10 is connected with power output circuit 5 with T8-7 serial connection back.Being the inverse-excitation type mode of operation between winding T1-2 and the T6-10, is the positive activation type mode of operation between winding T1-2 and the T8-7.Potential circuit 1 to be measured is for the direct current input or exchange input, and the frequency that exchanges input is 50Hz or 60Hz.

Switching power source chip 3 is a PWM control mode pattern, perhaps is PFC control mode pattern.Switching power source chip 3 is the digital control approach pattern, perhaps is the analog control mode pattern.

Switching power source chip 3 is provided with the extension switch, and it is the integration mode pattern, or discrete device mode pattern.Extending switch is former limit feedback system pattern, perhaps is secondary feedback system pattern.

Detect voltage follower circuit and be connected, and/or be connected power supply with other circuit with the AD mouth of single-chip microcomputer.

The principle of work of the utility model is following: potential circuit 1 to be measured inserts supply socket CN, and alternating voltage Vac to be measured is through obtaining the DC voltage of 1.4*Vac behind the current rectifying and wave filtering circuit.When switching power source chip 3 operate as normal; Because of switching power source chip 3 speed-sensitive switches; DC voltage produces the self induction voltage of upper frequency on the winding T1-2 of switch transformer; Through the magnetic force coupling of switch transformer 4, on the secondary winding T8-7 of switch transformer, produce the mutual voltage V2 of upper frequency.This mutual voltage can obtain the detection voltage Vad that is directly proportional with input voltage Vac after through output rectifying and wave-filtering.

Claims (9)

1. voltage detecting circuit; Comprise potential circuit to be measured (1), current rectifying and wave filtering circuit (2), switching power source chip (3), switch transformer (4), the power output circuit (5) that connects successively and detect voltage follower circuit; It is characterized in that switch transformer (4) is made up of the winding more than 2; It is the positive activation type mode of operation, perhaps inverse-excitation type mode of operation, perhaps positive and negative sharp combined type mode of operation.

2. voltage detecting circuit according to claim 1 is characterized in that said switch transformer (4) is made up of 3 windings, and it is respectively T1-2, T6-10 and T8-7; Winding T1-2 is connected with current rectifying and wave filtering circuit (2) with switching power source chip (3) serial connection back, and winding T6-10 is connected with power output circuit (5) with the T8-7 serial connection.

3. voltage detecting circuit according to claim 2 is characterized in that being the inverse-excitation type mode of operation between said winding T1-2 and the T6-10, is the positive activation type mode of operation between winding T1-2 and the T8-7.

4. according to each described voltage detecting circuit of claim 1-3, it is characterized in that said potential circuit to be measured (1) is direct current input or interchange input, the frequency of input is 50Hz or 60Hz.

5. voltage detecting circuit according to claim 4 is characterized in that said switching power source chip (3) is PWM control mode pattern, perhaps is PFC control mode pattern.

6. voltage detecting circuit according to claim 5 is characterized in that said switching power source chip (3) is the digital control approach pattern, perhaps is the analog control mode pattern.

7. voltage detecting circuit according to claim 6 is characterized in that said switching power source chip (3) is provided with the extension switch, and it is the integration mode pattern, or discrete device mode pattern.

8. voltage detecting circuit according to claim 7 is characterized in that said extension switch is a former limit feedback system pattern, perhaps is secondary feedback system pattern.

9. voltage detecting circuit according to claim 8 is characterized in that said detection voltage follower circuit is connected with the AD mouth of single-chip microcomputer, and/or is connected power supply with other circuit.

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