Start-up apparatus for battery management circuit and battery management system having the same
A start-up apparatus for a battery management circuit and a battery management system having the same are provided. The start-up apparatus for the battery management circuit includes a transformer, a switch circuit, a control circuit, and a rectifier circuit. The transformer includes a primary winding, an auxiliary winding, and a secondary winding. A first terminal of the primary winding is coupled to a first external power path. A first terminal of the switch circuit is coupled to a second terminal of the primary winding, and a second terminal of the switch circuit is coupled to a second external power path. The control circuit is coupled to the auxiliary winding for receiving power and controls a conduction state of the switch circuit. The rectifier circuit is coupled to the secondary winding of the transformer and supplies power to the battery management circuit.
1. A start-up apparatus of a battery management circuit, the start-up apparatus comprising:
a transformer comprising a primary winding, an auxiliary winding, and a secondary winding, wherein a first terminal of the primary winding is coupled to a first external power path;
a switch circuit, wherein a first terminal of the switch circuit is coupled to a second terminal of the primary winding, and a second terminal of the switch circuit is coupled to a second external power path;
a control circuit coupled to the auxiliary winding to receive power, wherein the control circuit controls a conduction state of the switch circuit; and
a rectifier circuit coupled to the secondary winding of the transformer, wherein the rectifier circuit supplies power to the battery management circuit,
wherein the start-up apparatus is supplied with power from an external power source through the first external power path and the second external power path.
2. The start-up apparatus according to claim 1 , wherein the switch circuit comprises:
a power transistor, wherein a first terminal of the power transistor is coupled to the second terminal of the primary winding, and a control terminal of the power transistor is coupled to the control circuit; and
a current limiting resistor, wherein a first terminal of the current limiting resistor is coupled to a second terminal of the power transistor, and a second terminal of the current limiting resistor is coupled to the second external power path.
3. The start-up apparatus according to claim 1 , wherein the control circuit comprises:
an auxiliary power circuit, coupled to a first terminal of the auxiliary winding of the transformer, configured to provide an auxiliary power by using power of the auxiliary winding; and
a pulse width modulation circuit coupled to the auxiliary power circuit to receive the auxiliary power, so as to generate a pulse signal to a control terminal of the switch circuit to control the conduction state of the switch circuit.
4. The start-up apparatus according to claim 3 , wherein the pulse width modulation circuit comprises:
a first resistor, wherein a first terminal of the first resistor is coupled to the first external power path, and a second terminal of the first resistor is coupled to a control terminal of a power transistor of the switch circuit; and
a first diode, wherein a first terminal of the first diode is coupled to the second terminal of the first resistor, and a second terminal of the first diode is coupled to a source of the switch circuit.
5. The start-up apparatus according to claim 4 , wherein the pulse width modulation circuit further comprises:
a Zener diode, wherein a first terminal of the Zener diode is coupled to the second terminal of the first resistor, and a second terminal of the Zener diode is coupled to the second external power path.
6. The start-up apparatus according to claim 4 , wherein the auxiliary power circuit comprises:
a second resistor, wherein a first terminal of the second resistor is coupled to the first terminal of the auxiliary winding, and a second terminal of the auxiliary winding is coupled to the second external power path;
a first capacitor, wherein a first terminal of the first capacitor is coupled to a second terminal of the second resistor, and a second terminal of the first capacitor s coupled to the second terminal of the first resistor; and
a second diode, wherein a first terminal of the second diode is coupled to the first terminal of the auxiliary winding, and a second terminal of the second diode is coupled to the second external power path.
7. The start-up apparatus according to claim 4 , wherein the auxiliary power circuit comprises:
a second resistor, wherein a first terminal of the second resistor is coupled to the first terminal of the auxiliary winding, and a second terminal of the auxiliary winding is coupled to the second external power path;
a first capacitor, wherein a first terminal of the first capacitor is coupled to a second terminal of the second resistor, and a second terminal of the first capacitor is coupled to the second terminal of the first resistor;
a second diode, wherein a first terminal of the second diode is coupled to the first terminal of the auxiliary winding;
a second capacitor, wherein a first terminal of the second capacitor is coupled to a second terminal of the second diode, and a second terminal of the second capacitor is coupled to the second external power path; and
a third resistor, wherein a first terminal of the third resistor is coupled to the second terminal of the second diode, and a second terminal of the third resistor is coupled to the second external power path.
8. The start-up apparatus according to claim 1 , further comprising:
a trigger circuit coupled to the control circuit, wherein the trigger circuit determines whether to disable the control circuit according to a control command of the battery management circuit.
9. The start-up apparatus according to claim 8 , wherein the trigger circuit comprises:
a photocoupler, wherein a light emitting part of the photocoupler is coupled to the battery management circuit, a first terminal of a light receiving part of the photocoupler is coupled to the control circuit, and a second terminal of the light receiving part is coupled to the second external power path.
10. The start-up apparatus according to claim 1 , further comprising:
an excitation circuit, wherein a first terminal of the excitation circuit is coupled to the first terminal of the primary winding, and a second terminal of the excitation circuit is coupled to the second terminal of the primary winding.
11. The start-up apparatus according to claim 10 , wherein the excitation circuit comprises:
a resistor, wherein a first terminal of the resistor is coupled to the first terminal of the primary winding;
a capacitor, wherein a first terminal of the capacitor is coupled to the first terminal of the primary winding; and
a diode, wherein a first terminal of the diode is coupled to a second terminal of the resistor and a second terminal of the capacitor, and a second terminal of the diode is coupled to the second terminal of the primary winding.
12. A battery management system, comprising:
a battery module;
a battery management circuit coupled to the battery module to manage a power amount of the battery module, wherein the battery module supplies power to the battery management circuit when the battery module has sufficient power to supply the battery management circuit; and
a start-up apparatus coupled to the battery management circuit, wherein the start-up apparatus comprises:
a transformer comprising a primary winding, an auxiliary winding, and a secondary winding, wherein a first terminal of the primary winding is coupled to a first external power path;
a switch circuit, wherein a first terminal of the switch circuit is coupled to a second terminal of the primary winding, and a second terminal of the switch circuit is coupled to a second external power path;
a control circuit coupled to the auxiliary winding to receive power, wherein the control circuit controls a conduction state of the switch circuit; and
a rectifier circuit coupled to the secondary winding of the transformer, wherein the rectifier circuit supplies power to the battery management circuit when the battery module does not have sufficient power to supply the battery management circuit.
13. The battery management system according to claim 12 , wherein the battery management circuit comprises:
a battery management chip coupled to the battery module to manage the power amount of the battery module; and
a voltage regulation circuit coupled to the battery module to receive power, wherein the voltage regulation circuit supplies power to the battery management chip by using power provided from the battery module when the battery module has sufficient power, and the voltage regulation circuit supplies power to the battery management chip by using power provided from the rectifier circuit when the battery module does not have sufficient power.
14. The battery management system according to claim 13 , wherein the voltage regulation circuit comprises:
a first diode, wherein an anode of the first diode is coupled to the battery module to receive power;
a second diode, wherein an anode of the second diode is coupled to the rectifier circuit to receive power; and
a voltage regulator, wherein an input terminal of the voltage regulator is coupled to a cathode of the first diode and a cathode of the second diode, and an output terminal of the voltage regulator supplies power to the battery management chip.
15. The battery management system according to claim 12 , wherein the switch circuit comprises:
a power transistor, wherein a first terminal of the power transistor is coupled to the second terminal of the primary winding, and a control terminal of the power transistor is coupled to the control circuit; and
a current limiting resistor, wherein a first terminal of the current limiting resistor is coupled to a second terminal of the power transistor, and a second terminal of the current limiting resistor is coupled to the second external power path.
16. The battery management system according to claim 12 , wherein the control circuit comprises:
an auxiliary power circuit, coupled to a first terminal of the auxiliary winding of the transformer, configured to provide an auxiliary power by using power of the auxiliary winding; and
a pulse width modulation circuit coupled to the auxiliary power circuit to receive the auxiliary power, so as to generate a pulse signal to a control terminal of the switch circuit to control the conduction state of the switch circuit.
17. The battery management system according to claim 16 , wherein the pulse width modulation circuit comprises:
a first resistor, wherein a first terminal of the first resistor is coupled to the first external power path, and a second terminal of the first resistor is coupled to a control terminal of a power transistor of the switch circuit; and
a first diode, wherein a first terminal of the first diode is coupled to the second terminal of the first resistor, and a second terminal of the first diode is coupled to a source of the switch circuit.
18. The battery management system according to claim 17 , wherein the pulse width modulation circuit further comprises:
a Zener diode, wherein a first terminal of the Zener diode is coupled to the second terminal of the first resistor, and a second terminal of the Zener diode is coupled to the second external power path.
19. The battery management system according to claim 17 , wherein the auxiliary power circuit comprises:
a second resistor, wherein a first terminal of the second resistor is coupled to the first terminal of the auxiliary winding, and a second terminal of the auxiliary winding is coupled to the second external power path;
a first capacitor, wherein a first terminal of the first capacitor is coupled to a second terminal of the second resistor, and a second terminal of the first capacitor is coupled to the second terminal of the first resistor; and
a second diode, wherein a first terminal of the second diode is coupled to the first terminal of the auxiliary winding, and a second terminal of the second diode is coupled to the second external power path.
20. The battery management system according to claim 17 , wherein the auxiliary power circuit comprises:
a second resistor, wherein a first terminal of the second resistor is coupled to the first terminal of the auxiliary winding, and a second terminal of the auxiliary winding is coupled to the second external power path;
a first capacitor, wherein a first terminal of the first capacitor is coupled to a second terminal of the second resistor, and a second terminal of the first capacitor is coupled to the second terminal of the first resistor;
a second diode, wherein a first terminal of the second diode is coupled to the first terminal of the auxiliary winding;
a second capacitor, wherein a first terminal of the second capacitor is coupled to a second terminal of the second diode, and a second terminal of the second capacitor is coupled to the second external power path; and
a third resistor, wherein a first terminal of the third resistor is coupled to the second terminal of the second diode, and a second terminal of the third resistor is coupled to the second external power path.
21. The battery management system according to claim 12 , further comprising:
a trigger circuit coupled to the control circuit, wherein the trigger circuit determines whether to disable the control circuit according to a control command of the battery management circuit.
22. The battery management system according to claim 21 , wherein the trigger circuit comprises:
a photocoupler, wherein a light emitting part of the photocoupler is coupled to the battery management circuit, a first terminal of a light receiving part of the photocoupler is coupled to the control circuit, and a second terminal of the light receiving part is coupled to the second external power path.
23. The battery management system according to claim 12 , further comprising:
an excitation circuit, wherein a first terminal of the excitation circuit is coupled to the first terminal of the primary winding, and a second terminal of the excitation circuit is coupled to the second terminal of the primary winding.
24. The battery management system according to claim 23 , wherein the excitation circuit comprises:
a resistor, wherein a first terminal of the resistor is coupled to the first terminal of the primary winding;
a capacitor, wherein a first terminal of the capacitor is coupled to the first terminal of the primary winding; and
a diode, wherein a first terminal of the diode is coupled to a second terminal of the resistor and a second terminal of the capacitor, and a second terminal of the diode is coupled to the second terminal of the primary winding.