CN103197249A - Low power consumption detection circuit for battery power - Google Patents

Abstract

The invention belongs to the field of detection circuits, and particularly relates to a low power consumption detection circuit for battery power. In the implementation, the low power consumption detection circuit for the battery power is based on a coulombmeter electronic quantity detection principle, and a correcting circuit is adopted to correct a counting circuit. The low power consumption detection circuit for the battery power is simple in circuit structure, low in power consumption suitable for normally open working, and capable of detecting the battery power in a standby mode.

Description

Low-power consumption battery electric quantity testing circuit

Technical field

The invention belongs to the testing circuit field, relate in particular to low-power consumption battery electric quantity testing circuit.

Background technology

At present, detection to the dump energy of the rechargeable battery in the portable products such as wireless and cell phone, MP3, net book and panel computer is extremely important, accurate electric weight detects and can make handheld device take full advantage of its battery, and allow the system designer to adopt compact battery, reduce the loss of data risk, increase customer satisfaction degree.

Current main battery electric quantity detection technique mainly comprises following two kinds:

(1) based on the electric weight detection technique of voltage

Battery electric quantity detection means is the most intuitively measured its voltage curve exactly.According to cell voltage and temperature, set up two-dimensional polling list lattice and preserve specified battery parameter, in order to be used for estimating dump energy.The discharge curve of battery can change with discharge rate, can change with cell degradation, relies on two-dimentional table lookup dump energy can have error.

(2) based on the electric weight detection technique of coulombmeter

By measuring the electric charge that flows into and flow out battery, utilize a coulomb counter keeps track battery electric quantity precision height.The typical commercial product has the BQ28550 of TI company, uses an ADC to measure cell voltage, sets up the mathematical model of the correspondence between cell voltage/electric weight/temperature, andacquisition battery 100% fills the electric weight when satisfying.Simultaneously, use integrator ADC to detect the electric charge that flows out battery, thereby obtain dump energy.The DS2874 of Maxim company uses 16bit ADC to detect the electric current of inflow/outflow battery, and 10bit ADC detects cell voltage, in conjunction with the cell voltage electric quantity curve of storing among the EEPROM, obtains current battery electric quantity information.

But existing battery electric quantity testing circuit exists circuit structure complexity, power consumption big, and the problem that can't detect battery electric quantity under the holding state.

Summary of the invention

The object of the present invention is to provide a kind of low-power consumption battery electric quantity testing circuit, be intended to solve present low-power consumption battery electric quantity testing circuit and exist circuit structure complexity, power consumption big, and the problem that can't detect battery electric quantity under the holding state.

The present invention is achieved in that low-power consumption battery electric quantity testing circuit comprises:

The sampling resistor Rsens that is connected with anode or negative pole;

The electric current that flows through described sampling resistor Rsens is sampled, and the current sampling circuit of output sampled result;

Be connected with described current sampling circuit, described sampled result is handled, and the comparator circuit of output processing signals;

Be connected with described comparator circuit, according to described processing signals, generate the counting circuit of charge value; And

Be connected with described counting circuit, be used for proofreading and correct the correcting circuit of described counting circuit.

In the said structure, described current sampling circuit comprises:

Input resistance R1, input resistance R2, integrating capacitor C1 and the first operational amplifier U1;

First end of described input resistance R1 and first end of input resistance R2 connect the two ends of described sampling resistor Rsens respectively, second end of described input resistance R1 and second end of input resistance R2 connect inverting input and the in-phase input end of the described first operational amplifier U1 respectively, and described integrating capacitor C1 is connected between the inverting input and output terminal of the described first operational amplifier U1.

In the said structure, described comparator circuit comprises:

The second operational amplifier U2 and the 3rd operational amplifier U3;

The in-phase input end of the described second operational amplifier U2 connects the output terminal of the described first operational amplifier U1, the inverting input of the described second operational amplifier U2 connects first reference voltage, the inverting input of described the 3rd operational amplifier U3 connects the output terminal of the described first operational amplifier U1, the in-phase input end of described the 3rd operational amplifier U3 connects second reference voltage, the output terminal of the described second operational amplifier U2 connects described counting circuit by a totalizer, the described counting circuit of output termination of described the 3rd operational amplifier U3.

In the said structure, described counting circuit is counter U4, the described totalizer of subtrahend input termination of described counter U4, the output terminal of described the 3rd operational amplifier U3 of addend input termination of described counter U4.

In the said structure, described correcting circuit is an EEPROM who stores the self-discharge of battery curve in advance, and described EEPROM connects the subtrahend input end of described counter U4 by described totalizer.

In the present invention, low-power consumption battery electric quantity testing circuit detects principle based on the coulombmeter electric weight, and adopts correcting circuit counts corrected circuit, and this low-power consumption battery electric quantity testing circuit circuit structure is simple, power consumption is little, and be fit to often go into operation work, can detect the electric weight of battery under the holding state.

Description of drawings

Fig. 1 is the circuit module figure of the low-power consumption battery electric quantity testing circuit that provides of the embodiment of the invention;

Fig. 2 is the circuit structure diagram of the low-power consumption battery electric quantity testing circuit that provides of the embodiment of the invention.

Embodiment

In order to make purpose of the present invention, technical scheme and advantage clearer, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explaining the present invention, and be not used in restriction the present invention.

Fig. 1 shows the circuit module structure of the low-power consumption battery electric quantity testing circuit that the embodiment of the invention provides, and for convenience of explanation, only shows the part relevant with the embodiment of the invention, and details are as follows.

Low-power consumption battery electric quantity testing circuit comprises:

The sampling resistor Rsens that is connected with anode or negative pole;

The electric current of convection current over-sampling resistance R sens is sampled, and thecurrent sampling circuit 100 of output sampled result;

Be connected withcurrent sampling circuit 100, sampled result is handled, and thecomparator circuit 200 of output processing signals;

Be connected withcomparator circuit 200, according to processing signals, generate the countingcircuit 300 of charge value; And

Be connected withcounting circuit 300, be used for the correctingcircuit 400 of counts correctedcircuit 300.

Fig. 2 shows the circuit structure of the low-power consumption battery electric quantity testing circuit that the embodiment of the invention provides, and for convenience of explanation, only shows the part relevant with the embodiment of the invention, and details are as follows.

As one embodiment of the invention,current sampling circuit 100 comprises:

Input resistance R1, input resistance R2, integrating capacitor C1 and the first operational amplifier U1;

First end of input resistance R1 and first end of input resistance R2 connect the two ends of sampling resistor Rsens respectively, second end of input resistance R1 and second end of input resistance R2 connect inverting input and the in-phase input end of the first operational amplifier U1 respectively, and integrating capacitor C1 is connected between the inverting input and output terminal of the first operational amplifier U1.

As one embodiment of the invention,comparator circuit 200 comprises:

The second operational amplifier U2 and the 3rd operational amplifier U3;

The in-phase input end of the second operational amplifier U2 connects the output terminal of the first operational amplifier U1, the inverting input of the second operational amplifier U2 meets the first reference voltage VREFP, the inverting input of the 3rd operational amplifier U3 connects the output terminal of the first operational amplifier U1, the in-phase input end of the 3rd operational amplifier U3 meets the second reference voltage VREFN, the output terminal of the second operational amplifier U2 connects the outputtermination counting circuit 300 ofcounting circuit 300, the three operational amplifier U3 by a totalizer.

As one embodiment of the invention, countingcircuit 300 is counter U4, the subtrahend input termination totalizer of counter U4, the output terminal of addend input termination the 3rd operational amplifier U3 of counter U4.

As one embodiment of the invention, correctingcircuit 400 is an EEPROM who stores the self-discharge of battery curve in advance, and EEPROM connects the subtrahend input end of described counter U4 by totalizer.

The principle of work of low-power consumption battery electric quantity testing circuit is as follows:

The electric current that flows into/flow out battery is converted to voltage signal by sampling resistor Rsens:

V_sens＝I×R_sens

Be input to low-power consumption battery electric quantity testing circuit.

Current sampling circuit 100 is handled input signal in real time, and input signal is carried out integral operation.When input signal for just, integrating capacitor C1 discharge; When input signal for negative, integrating capacitor C1 charging:

$V_o/V_i=\frac{1}{\mathrm{sRC}}$

$V_o\left(t\right)=\frac{1}{\mathrm{RC}}\underset{0}{\∫}{V}_i\×u\left(t\right)\mathrm{dt}=\frac{R_{\mathrm{sens}}}{\mathrm{RC}}\underset{0}{\∫}I\left(t\right)\mathrm{dt}$

Current sampling circuit 100output comparator circuits 200.

Comparator circuit 200 connects input signal and reference voltage is compared, and input signal is exported downward spill over during less than the second reference voltage VREFN, and the integrating capacitor that resets simultaneously C1 begins new integral operation; Input signal is during greater than the first reference voltage VREFP, and output is spill over upwards, and the integrating capacitor that resets simultaneously C1 begin new integral operation, the outputdriving counting circuit 300 ofcomparator circuit 200.

The output signal that countingcircuit 300 receives fromcomparator circuit 200, the input signal ofcounting circuit 300 is narrow pulse signal, pulse width equals the response time that addscomparator circuit 200 reset time of integrating capacitor C1.Each downward overflow pulse signal drives countingcircuit 300 and adds 1 counting, and each overflow pulse signal that makes progress drives countingcircuit 300 and subtracts 1 counting.

There is the self discharge behavior in battery, and this part self discharge electric current can not flow through sampling resistor Rsens, can not be perceived, and need test one Battery pack self discharge curve, and store in the non-volatility memorizer such as EEPROM/FLASH.This curve has characterized the self-discharge of battery behavior, i.e. battery dump energy and temperature/time relation, and the self-discharge of battery curve is used for counts correctedcircuit 300, and it drives the 32KHz clock that clock can use Chang Kaimo piece RTC.

In embodiments of the present invention, low-power consumption battery electric quantity testing circuit detects principle based on the coulombmeter electric weight, and adopt correcting circuit counts corrected circuit, this low-power consumption battery electric quantity testing circuit circuit structure is simple, power consumption is little, and be fit to often go into operation work, can detect the electric weight of battery under the holding state.

The above only is preferred embodiment of the present invention, not in order to limiting the present invention, all any modifications of doing within the spirit and principles in the present invention, is equal to and replaces and improvement etc., all should be included within protection scope of the present invention.

Claims (5)

1. a low-power consumption battery electric quantity testing circuit is characterized in that, described low-power consumption battery electric quantity testing circuit comprises:

The sampling resistor Rsens that is connected with anode or negative pole;

The electric current that flows through described sampling resistor Rsens is sampled, and the current sampling circuit of output sampled result;

Be connected with described current sampling circuit, described sampled result is handled, and the comparator circuit of output processing signals;

Be connected with described comparator circuit, according to described processing signals, generate the counting circuit of charge value; And

Be connected with described counting circuit, be used for proofreading and correct the correcting circuit of described counting circuit.

2. low-power consumption battery electric quantity testing circuit as claimed in claim 1 is characterized in that described current sampling circuit comprises:

Input resistance R1, input resistance R2, integrating capacitor C1 and the first operational amplifier U1;

First end of described input resistance R1 and first end of input resistance R2 connect the two ends of described sampling resistor Rsens respectively, second end of described input resistance R1 and second end of input resistance R2 connect inverting input and the in-phase input end of the described first operational amplifier U1 respectively, and described integrating capacitor C1 is connected between the inverting input and output terminal of the described first operational amplifier U1.

3. low-power consumption battery electric quantity testing circuit as claimed in claim 2 is characterized in that described comparator circuit comprises:

The second operational amplifier U2 and the 3rd operational amplifier U3;

The in-phase input end of the described second operational amplifier U2 connects the output terminal of the described first operational amplifier U1, the inverting input of the described second operational amplifier U2 connects first reference voltage, the inverting input of described the 3rd operational amplifier U3 connects the output terminal of the described first operational amplifier U1, the in-phase input end of described the 3rd operational amplifier U3 connects second reference voltage, the output terminal of the described second operational amplifier U2 connects described counting circuit by a totalizer, the described counting circuit of output termination of described the 3rd operational amplifier U3.

4. low-power consumption battery electric quantity testing circuit as claimed in claim 3, it is characterized in that, described counting circuit is counter U4, the described totalizer of subtrahend input termination of described counter U4, the output terminal of described the 3rd operational amplifier U3 of addend input termination of described counter U4.

5. low-power consumption battery electric quantity testing circuit as claimed in claim 4 is characterized in that, described correcting circuit is an EEPROM who stores the self-discharge of battery curve in advance, and described EEPROM connects the subtrahend input end of described counter U4 by described totalizer.

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