CIRCUIT AND SYSTEM AND METHOD FOR CONTROLLING BATTERY

• US 20130119938A1
• Filed: 01/16/2012
• Published: 05/16/2013
• Est. Priority Date: 11/16/2011
• Status: Active Grant

• Current Assignee: VIA Technologies Incorporated (VIA Technologies)
• Original Assignee: VIA Technologies Incorporated (VIA Technologies)
• Inventors: Ma, Chun-Chen
• Granted Patent: US 8,952,662 B2
• Time in Patent Office: Days
• US Class Current: 320/134
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]

Abstract

A battery control circuit for balancing a battery includes a voltage detector, a controller, a balancing device, and a switch. The voltage detector is configured to detect a voltage difference of the battery so as to generate a detecting signal. The controller is configured to generate a control signal according to the detecting signal. The switch is coupled between the battery and the balancing device, and is opened or closed according to the control signal, wherein if the voltage difference is greater than a threshold value, the switch is closed and the balancing device draws a load current from the battery, and if the voltage difference is smaller than or equal to the threshold value, the switch is opened and the balancing device is not capable of drawing any current.

Claims

1. A battery control circuit for balancing a battery, comprising:

a voltage detector, detecting a voltage difference of the battery so as to generate a detecting signal;

a controller, generating a control signal according to the detecting signal;

a balancing device; and

a switch, coupled between the battery and the balancing device, being opened or closed according to the control signal,

wherein if the voltage difference is greater than a threshold value, the switch is closed and the balancing device draws a load current from the battery, and if the voltage difference is smaller than or equal to the threshold value, the switch is opened and the balancing device is not capable of drawing any current.

2. The battery control circuit as claimed in claim 1, wherein the voltage detector comprises:

an operational amplifier (OP), having a positive input end, a negative input end, and an output end, wherein the output end is configured to output the detecting signal;

a first resistor, coupled between the negative input end and the output end;

a second resistor, coupled between the negative input end and a ground voltage;

a third resistor, coupled between the positive input end and the switch; and

a fourth resistor, coupled between the positive input end and the ground voltage.

3. The battery control circuit as claimed in claim 1, wherein the controller comprises:

a Zener diode, having a cathode and an anode coupled to a ground voltage;

a fifth resistor, coupled between the cathode and a first node;

a sixth resistor, coupled between the voltage detector and the first node; and

an OR gate, having two input ends coupled to the first node and an output end coupled to the switch, wherein the output end is configured to output the control signal.

4. The battery control circuit as claimed in claim 1, wherein the switch comprises:

a first transistor, coupled between a second node and the balancing device, and having a gate coupled to a third node;

a second transistor, coupled between a fourth node and a ground voltage, and having a gate coupled to a fifth node;

a seventh resistor, coupled between the second node and the third node;

an eighth resistor, coupled between the third node and the fourth node; and

a ninth resistor, coupled between the fifth node and the ground voltage,

and the balancing device comprises;

a tenth resistor, coupled between the switch and the ground voltage,

wherein the second node is coupled to the battery and is coupled to the voltage detector, and the fifth node is couple to the controller.

5. The battery control circuit as claimed in claim 4, wherein the first transistor is a PMOS transistor (P-channel Metal-Oxide-Semiconductor Field-Effect Transistor), and the second transistor is an NMOS transistor (N-channel Metal-Oxide-Semiconductor Field-Effect Transistor).

6. A battery control system, comprising:

a battery, having a voltage difference;

a voltage detector, coupled to the battery, and detecting the voltage difference so as to generate a detecting signal;

a controller, generating a control signal according to the detecting signal;

a balancing device; and

a switch, coupled between the battery and the balancing device, being opened or closed according to the control signal,

wherein if the voltage difference is greater than a threshold value, the switch is closed and the balancing device draws a load current from the battery, and if the voltage difference is smaller than or equal to the threshold value, the switch is opened and the balancing device is not capable of drawing any current.

7. The battery control system as claimed in claim 6, wherein the voltage detector comprises:

an operational amplifier (OP), having a positive input end, a negative input end, and an output end, wherein the output end is configured to output the detecting signal;

a first resistor, coupled between the negative input end and the output end;

a second resistor, coupled between the negative input end and a ground voltage;

a third resistor, coupled between the positive input end and the switch; and

a fourth resistor, coupled between the positive input end and the ground voltage.

8. The battery control system as claimed in claim 6, wherein the controller comprises:

a Zener diode, having a cathode and an anode coupled to a ground voltage;

a fifth resistor, coupled between the cathode and a first node;

a sixth resistor, coupled between the voltage detector and the first node; and

an OR gate, having two input ends coupled to the first node and an output end coupled to the switch, wherein the output end is configured to output the control signal.

9. The battery control system as claimed in claim 6, wherein the switch comprises:

a first transistor, coupled between a second node and the balancing device, and having a gate coupled to a third node;

a second transistor, coupled between a fourth node and a ground voltage, and having a gate coupled to a fifth node;

a seventh resistor, coupled between the second node and the third node;

an eighth resistor, coupled between the third node and the fourth node; and

a ninth resistor, coupled between the fifth node and the ground voltage,

and the balancing device comprises;

a tenth resistor, coupled between the switch and the ground voltage, wherein the second node is coupled to the battery and is coupled to the voltage detector, and the fifth node is couple to the controller.

10. The battery control system as claimed in claim 6, further coupled to a processor configured to obtain the detecting signal.

11. A battery control method for balancing a battery, comprising the steps of:

detecting a voltage difference of the battery so as to generate a detecting signal;

generating a control signal according to the detecting signal;

drawing a load current from the battery by a balancing device if the voltage difference is greater than a threshold value; and

not drawing current from the battery by the balancing device if the voltage difference is smaller than or equal to the threshold value.

12. The battery control method as claimed in claim 11, wherein the voltage difference is detected by a voltage detector, and wherein the voltage detector comprises:

an operational amplifier (OP), having a positive input end, a negative input end, and an output end, wherein the output end is configured to output the detecting signal;

a first resistor, coupled between the negative input end and the output end;

a second resistor, coupled between the negative input end and a ground voltage;

a third resistor, coupled between the positive input end and the switch; and

a fourth resistor, coupled between the positive input end and the ground voltage.

13. The battery control method as claimed in claim 11, wherein the control signal is generated by a controller, and wherein the controller comprises:

a Zener diode, having a cathode and an anode coupled to a ground voltage;

a fifth resistor, coupled between the cathode and a first node;

a sixth resistor, coupled between the voltage detector and the first node; and

an OR gate, having two input ends coupled to the first node and an output end coupled to the switch, wherein the output end is configured to output the control signal.

14. The battery control method as claimed in claim 11, wherein the steps of drawing or not drawing a load current from the battery by a balancing device is performed by a switch and the balancing device, wherein the switch comprises:

a first transistor, coupled between a second node and the balancing device, and having a gate coupled to a third node;

a second transistor, coupled between a fourth node and a ground voltage, and having a gate coupled to a fifth node;

a seventh resistor, coupled between the second node and the third node;

an eighth resistor, coupled between the third node and the fourth node; and

a ninth resistor, coupled between the fifth node and the ground voltage,

and wherein the balancing device comprises;

a tenth resistor, coupled between the switch and the ground voltage,

wherein the second node is coupled to the battery and is coupled to the voltage detector, and the fifth node is couple to the controller.

15. The battery control method as claimed in claim 14, wherein the first transistor is a PMOS transistor (P-channel Metal-Oxide-Semiconductor Field-Effect Transistor), and the second transistor is an NMOS transistor (N-channel Metal-Oxide-Semicondutor Field-Effect Transistor).