CN105375541A - Switching type charging circuit - Google Patents

Abstract

A switching charging circuit includes a power management chip, a processor, and a feedback circuit. Among them, the power management chip is used to charge the battery with different power output; the processor is used to output control signals to control whether the power management chip works and provide preset current value and preset voltage value; the feedback circuit receives the preset current value and The preset voltage value is used for current comparison and voltage comparison, and a feedback signal is provided to the power management chip according to the comparison result, thereby adjusting the power output of the power management chip; The power output is reduced when the charging voltage is higher than the preset voltage value, and the power output is increased when the charging current is smaller than the preset current value or the charging voltage is smaller than the preset voltage value. The invention controls the charging circuit by adding a power supply chip, thereby effectively improving the charging efficiency and reducing unnecessary energy loss.

Description

Switching charging circuit

technical field

The invention relates to a charging circuit, in particular to a switching charging circuit controlled by a power chip.

Background technique

In the system platform of some electronic products, the architecture of the linear charging circuit is generally used as the charging circuit. Under normal circumstances, the charging efficiency of the linear charging circuit is not high, and during the charging process, there is a variable voltage difference between the input voltage and the battery voltage, and this voltage difference mainly falls on the electronic devices between the input terminal and the battery. Necessary energy loss, especially when the charging current is relatively large, this energy loss will be greater.

Contents of the invention

In view of this, it is necessary to provide a switching charging circuit controlled by a power chip to improve the structure of the linear charging circuit, thereby improving charging efficiency and reducing unnecessary energy loss.

A switching charging circuit provided by an embodiment of the present invention includes a power management chip, a processor, and a feedback circuit. Among them, the power management chip is used to charge the battery with different power outputs; the processor is used to output control signals to control whether the power management chip works and to provide preset current values and preset voltage values; the feedback circuit is connected to the power management chip, Between the processor and the battery, current comparison and voltage comparison are performed by receiving the preset current value and preset voltage value of the processor, and a feedback signal is provided to the power management chip according to the comparison result, thereby adjusting the power output of the power management chip; the power supply The management chip reduces the power output when the charging current of the battery is larger than the preset current value or the charging voltage of the battery is larger than the preset voltage value, and increases the power when the charging current is smaller than the preset current value or the charging voltage is lower than the preset voltage value output.

Preferably, the switching charging circuit further includes a switch circuit, and the switch circuit is electrically connected between the power management chip and the processor to control the operation of the power management chip.

Preferably, the switch circuit includes a switch element, the switch element includes a first conduction terminal, a second conduction terminal and a controlled terminal, the first conduction terminal is electrically connected to the enable terminal of the power management chip, and the second conduction terminal is grounded , the controlled end is electrically connected to the processor to receive a control signal from the processor to control whether the power management chip works.

Preferably, the switching element is a field effect transistor, and the drain, source and gate of the field effect transistor serve as the first conduction terminal, the second conduction terminal and the controlled terminal respectively.

Preferably, the switch circuit further includes a first resistor, and the first resistor is electrically connected between the first conduction terminal and the input terminal of the power management chip.

Preferably, the feedback circuit includes a mixer, a first error amplifier, a second error amplifier, a third error amplifier, a first digital-to-analog converter and a second digital-to-analog converter. The first input terminal and the second input terminal of the first error amplifier are respectively connected to both ends of the sampling resistor to receive the charging current of the battery and output the amplified current; the input terminal of the first digital-to-analog converter is electrically connected to the processor to receive the processor The preset current value is converted into the required current reference value; the first input terminal of the second error amplifier is electrically connected to the output terminal of the first error amplifier, and the second input terminal is electrically connected to the output of the first digital-to-analog converter terminal, the second error amplifier is used to compare the amplified current with the current reference value and output the current comparison result; the input terminal of the second digital-to-analog converter is electrically connected to the processor, and is used to convert the preset voltage value sent by the processor is the required voltage reference value; the first input terminal of the third error amplifier is electrically connected to the input terminal of the battery to obtain the charging voltage of the battery, the second input terminal is electrically connected to the output terminal of the second digital-to-analog converter, and the first The error amplifier is used to compare the charging voltage with the voltage reference value and output the voltage comparison result; the input terminals of the mixer are respectively connected to the output terminals of the second error amplifier and the output terminal of the third error amplifier, and the output terminals of the mixer are electrically Connected to the feedback terminal of the power management chip, the mixer is used to process the current comparison result and the voltage comparison result and feed back information to the power management chip.

Preferably, the feedback circuit further includes a feedback resistor, the first end of the feedback resistor is connected to the output end of the mixer, and the second end of the feedback resistor is connected to the feedback end of the power management chip.

Preferably, the feedback circuit further includes a second resistor, a third resistor and a capacitor, the capacitor is connected in parallel with the second resistor after being connected in series with the third resistor, and then connected to the second end of the feedback resistor to adjust the voltage of the feedback resistor.

Preferably, the switching charging circuit further includes a first field effect transistor, the first conducting end of the first field effect transistor is electrically connected to the output end of the power management chip, and the second conducting end of the first field effect transistor is connected to the input of the battery terminal, the controlled terminal of the first FET is connected to the processor, and the first FET is used to adjust the charging current to protect the battery.

Preferably, the first field effect transistor is a high-power field effect transistor, and the drain, source and gate of the high-power field effect transistor serve as the first conducting end, the second conducting end and the receiving end of the first field effect transistor respectively. console.

The above-mentioned switching charging circuit controls the charging circuit by adding a power chip, thereby effectively improving charging efficiency and reducing unnecessary energy loss.

Description of drawings

FIG. 1 is a schematic diagram of an embodiment of the switching charging circuit of the present invention.

Explanation of main component symbols

Power management chip 100

Processor 200

switch circuit 300

feedback circuit 400

battery 500

input terminal IN

Output terminal OUT

Enable terminal EN

Feedback terminal FB

First FET M1

Switching element M2

The first resistor R1

Second resistor R2

The third resistor R3

Sampling resistance Rs

Feedback resistance Rf

Capacitor C1

Mixer U1

First error amplifier U2

Second error amplifier U3

The third error amplifier U4

The first digital-to-analog converter DAC1

The second digital-to-analog converter DAC2

The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings.

detailed description

FIG. 1 is a block diagram of a switching charging circuit according to an embodiment of the present invention. In this embodiment, the switching charging circuit is used for charging the battery, which includes a power management chip 100 , a processor 200 , a switch circuit 300 , a feedback circuit 400 and a battery 500 . Wherein, the power management chip 100 is used to perform power management according to external feedback information to output electric energy of different powers to charge the battery 500, the processor 200 is used to output control instructions to control the power management chip 100, and the input terminal IN of the power management chip 100 Both the processor 200 and the external charging power supply are electrically connected to receive the power signal, and the switch circuit 300 is electrically connected between the enable terminal EN of the power management chip 100 and the processor 200 to receive the control signal of the processor 200, and then control the power supply. The management chip 100 and the feedback circuit 400 are connected between the power management chip 100, the processor 200 and the battery 500 to obtain corresponding electrical signals and provide feedback signals to the power management chip 100, thereby adjusting the power output of the output terminal OUT of the power management chip. In this embodiment, when the enable terminal EN receives a low-level signal, the power management chip 100 stops outputting power; when the enable terminal EN receives a high-level signal, the power management chip 100 continues to output power.

In addition, the first conduction terminal of the first field effect transistor M1 is connected to the output terminal OUT of the power management chip 100 through the sampling resistor Rs and the inductor L1, the second conduction terminal is connected to the input terminal of the battery 500, and the controlled terminal is connected to the processor 200. , the inductor L1 is used for energy storage. During the charging process, the first field effect transistor M1 receives the adjustment signal from the processor 200 to adjust the charging current of the battery in good time to protect the battery 500 . In this embodiment, the first field effect transistor M1 is a high-power field effect transistor, and the drain, source and gate of the high-power field effect transistor serve as the first conduction end and the second end of the first field effect transistor M1 respectively. The conduction terminal and the controlled terminal.

The switch circuit 300 further includes a first resistor R1 and a switch element M2, the switch element M2 includes a first conduction terminal, a second conduction terminal and a controlled terminal, wherein the first conduction terminal of the switch element M2 is electrically connected to the power management chip The enable terminal EN of 100 is electrically connected to an external charging power supply via the first resistor R1, the second conduction terminal of the switch element M2 is grounded, and the controlled terminal of the switch element M2 is electrically connected to the processor 200 to receive a control signal to control the power supply. The management chip 100 . In this embodiment, the switch element M2 is a field effect transistor, and its first conduction terminal, second conduction terminal and controlled terminal correspond to the drain, source and gate of the field effect transistor respectively. When charging is abnormal, the processor 200 outputs a high level to the switch element M2, and the switch element M2 is turned on, so that the enable terminal EN of the power management chip 100 receives a low level signal, and the power management chip 100 stops outputting electric energy to Charging of the battery 500 is stopped. In other implementation manners, other controlled switches or transistors may also be used to form the switch circuit 300 .

The feedback circuit 400 further includes a mixer U1, a first error amplifier U2, a second error amplifier U3, a third error amplifier U4, a first digital-to-analog converter DAC1, a second digital-to-analog converter DAC2, a capacitor C1, and a second resistor R2 , the third resistor R3 and the feedback resistor Rf.

Wherein, the first input terminal and the second input terminal of the first error amplifier U2 are respectively connected to both ends of the sampling resistor Rs to obtain the charging current of the battery and output the amplified current, and the output terminal of the first error amplifier U2 is electrically connected to the second error The first input terminal of the amplifier U3 and the input terminal of the first digital-to-analog converter DAC1 are connected to the processor 200 to receive a preset current value from the processor 200 . The second input terminal of the second error amplifier U3 is electrically connected to the output terminal of the first digital-to-analog converter DAC1, and the output terminal of the second error amplifier U3 is connected to an input terminal of the mixer U1. Here, the first digital-to-analog converter DAC1 is used to convert the preset current value sent by the processor 200 into a current reference value required by the second error amplifier U3, and the preset current value sent by the processor 200 can be set according to actual needs. The preset current value is positively correlated with the current reference value, and the second error amplifier U3 is used to compare the amplified current with the current reference value and output the current comparison result to the mixer U1.

The output terminal of the mixer U1 is connected to the first terminal of the feedback resistor Rf, and the second terminal of the mixer U1 is connected to the signal feedback terminal FB of the power management chip 100 via the feedback resistor Rf to output a feedback signal. The capacitor C1 in the feedback circuit 400 is connected in series with the third resistor R3 and then connected in parallel with the second resistor R2, and further connected to the second end of the feedback resistor Rf to adjust the voltage of the feedback resistor Rf. The mixer U1 is used to process the current comparison result and the voltage comparison result and output a feedback signal to the feedback terminal FB of the power management chip 100 .

When the feedback circuit performs current comparison, if the charging current of the battery is larger than the preset current value, the feedback signal received by the power management chip will be larger, and the power management chip will reduce the power output; if the charging current of the battery is larger than the preset current value Small, the feedback signal received by the power management chip is small, and the power management chip will increase the power output.

Specifically, the first error amplifier U2 obtains the charging current of the battery from both ends of the sampling resistor Rs and outputs an amplified current to the second error amplifier U3, wherein the current in the circuit is positively correlated with the output amplified current. The second error amplifier U3 compares the amplified current with a current reference value and outputs a current comparison result. When the charging current of the battery is larger than the current reference value, the current comparison result output by the second error amplifier U3 is a larger positive voltage value, and the output value of the mixer U1 is also a larger positive voltage value, and the power management chip 100 The signal feedback terminal FB receives the raised voltage value, thereby reducing the power output of the output terminal OUT. Here, the larger the voltage value received by the signal feedback terminal FB, the smaller the power output of the output terminal OUT ; When the charging current of the battery is smaller than the preset current value, the current comparison result output by the second error amplifier U3 is a smaller negative voltage value, and the output value of the mixer U1 is also a smaller negative voltage value, and the power management chip The signal feedback terminal FB of 100 receives the pulled-down voltage value, thereby increasing the power output of the output terminal OUT. Here, the smaller the voltage value received by the signal feedback terminal FB, the greater the power output of the output terminal OUT. Big. In this embodiment, the greater the difference between the charging current of the battery and the preset current value, the greater the value of the output current comparison result, and finally the greater the value of the current comparison result fed back to the signal feedback terminal FB of the power management chip 100. Big.

The first input end of the third error amplifier U4 is connected to the input end of the battery 500 to obtain the charging voltage of the battery, the second input end of the third error amplifier U4 is electrically connected to the output end of the second digital-to-analog converter DAC2, and the third error amplifier The output terminal of U4 is electrically connected to the other input terminal of the mixer U1. The input end of the second digital-to-analog converter DAC2 is electrically connected to the processor 200 to receive the preset voltage value sent by the processor 200, where the second digital-to-analog converter DAC2 is used to convert the preset voltage value sent by the processor 200 Converted to the voltage reference value required by the third error amplifier U4, the preset voltage value sent by the processor 200 can be set according to actual needs, wherein the preset voltage value is positively correlated with the voltage reference value. In this embodiment, the third error amplifier U4 is used to compare the battery voltage with a voltage reference value and output a voltage comparison result.

When the feedback circuit performs voltage comparison, if the charging voltage of the battery is higher than the preset voltage value, the feedback signal received by the power management chip will be larger, and the power management chip will reduce the power output; if the charging voltage of the battery is higher than the preset voltage value Small, the feedback signal received by the power management chip is small, and the power management chip will increase the power output.

Specifically, the third error amplifier U4 obtains the battery voltage of the battery 500 from the charging circuit, and compares the obtained battery voltage with a preset voltage value. When the battery voltage is greater than the preset voltage value, the voltage comparison result output by the third error amplifier U4 is a positive voltage value, and the output value of the mixer U1 is also a positive voltage value, and the signal feedback terminal FB of the power management chip 100 receives the received signal. Raise the voltage value, thereby reducing the power output of the output terminal OUT; when the voltage is smaller than the preset voltage value, the voltage comparison result output by the third error amplifier U4 is a negative voltage value, and the output value of the mixer U1 is also a negative voltage value value, the signal feedback terminal FB of the power management chip 100 receives the pulled-down voltage value, thereby increasing the power output of the output terminal OUT. In this embodiment, the greater the difference between the battery voltage and the preset voltage, the greater the value of the output voltage comparison result, and the greater the value of the voltage comparison result fed back to the signal feedback terminal FB of the power management chip 100. Big.

In this embodiment, the signal feedback terminal FB of the power management chip 100 can adjust the output of the output terminal OUT according to the magnitude of the feedback signal.

The aforementioned switching charging circuit improves charging efficiency and reduces unnecessary energy loss by improving the structure of the linear charging circuit.

Claims (10)

1. a switch type charging circuit, for charging to battery, is characterized in that, comprising:

Power management chip, for charging to described battery with different horsepower outputs;

Whether processor, work for exporting control signal to control described power management chip and provide pre-set current value and preset voltage value; And

Feedback circuit, be connected between described power management chip, described processor and described battery, current ratio is carried out respectively with the charging current of described battery and charging voltage comparatively and voltage compare to receive the described pre-set current value of described processor and described preset voltage value, and provide feed back signal to described power management chip according to comparative result, thus regulate the horsepower output of described power management chip;

Wherein, described power management chip charging voltage that is larger than described pre-set current value in the charging current of described battery or described battery reduces described horsepower output time larger than described preset voltage value, increases described horsepower output when described charging current is less than described pre-set current value or described charging voltage is less than described preset voltage value.

2. switch type charging circuit as claimed in claim 1, it is characterized in that, described switch type charging circuit also comprises switching circuit, and described switching circuit is electrically connected between described power management chip and described processor to control the work of described power management chip.

3. switch type charging circuit as claimed in claim 2, it is characterized in that, described switching circuit comprises switch element, first conduction terminal of described switch element is electrically connected the Enable Pin of described power management chip, second conduction terminal ground connection of described switch element, whether the controlled end of described switch element is electrically connected described processor and works to control power management chip with the control signal receiving described processor.

4. switch type charging circuit as claimed in claim 3, it is characterized in that, described switch element is a field effect transistor, and the drain electrode of described field effect transistor, source electrode and grid are respectively as described first conduction terminal of described switch element, described second conduction terminal and described controlled end.

5. switch type charging circuit as claimed in claim 3, it is characterized in that, described switching circuit also comprises the first resistance, and described first resistance is electrically connected between described first conduction terminal and the input of described power management chip.

6. switch type charging circuit as claimed in claim 1, it is characterized in that, described feedback circuit comprises:

First error amplifier, first input end and the second input are connected to the two ends of sample resistance to obtain described charging current and to export amplified current;

First digital to analog converter, input is electrically connected described processor to receive described pre-set current value, and described pre-set current value is converted to current reference value;

Second error amplifier, first input end is electrically connected the output of described first error amplifier, second input is electrically connected the output of described first digital to analog converter, and described second error amplifier is used for described amplified current and described current reference value to compare and output current comparative result;

Second digital to analog converter, input is electrically connected described processor to receive described preset voltage value, and described preset voltage value is converted to voltage reference value;

3rd error amplifier, first input end is electrically connected the input of described battery to obtain described charging voltage, second input is electrically connected the output of described second digital to analog converter, and described first error amplifier is used for described charging voltage and described voltage reference value to compare and output voltage comparative result; And

Blender, the input of described blender is connected to the output of described second error amplifier and the output of described 3rd error amplifier to receive described electric current comparative result and described voltage compare result, the output of described blender is electrically connected the feedback end of described power management chip, and described blender is for exporting described feedback signal to described power management chip.

7. switch type charging circuit as claimed in claim 6, it is characterized in that, described feedback circuit also comprises feedback resistance, and the first end of described feedback resistance is connected with the output of described blender, and the second end of described feedback resistance connects the feedback end of described power management chip.

8. switch type charging circuit as claimed in claim 7, it is characterized in that, described feedback circuit also comprises the second resistance, the 3rd resistance and electric capacity, described electric capacity is connected with described second resistor coupled in parallel with after described 3rd resistant series, and then connects described feedback resistance second end to adjust the voltage of described feedback resistance.

9. switch type charging circuit as claimed in claim 1; it is characterized in that; described switch type charging circuit also comprises the first field effect transistor; first conduction terminal of described first field effect transistor is electrically connected described power management chip output; second conduction terminal of described first field effect transistor connects the input of described battery; the controlled end of described first field effect transistor connects described processor, and described first field effect transistor is for adjusting described charging current to protect described battery.

10. switch type charging circuit as claimed in claim 9, it is characterized in that, described first field effect transistor is high-power field effect pipe, and the drain electrode of described high-power field effect pipe, source electrode and grid are respectively as described first conduction terminal of described first field effect transistor, described second conduction terminal and described controlled end.