Systems and methods for controlling battery current
A battery system comprising multiple battery packs. A battery pack of the battery packs includes a battery, voltage sense circuitry, a control circuit, a control switch and current regulation circuitry. The voltage sense circuitry senses a battery voltage of the battery and an input voltage of the battery pack. The control circuit is coupled to the sense circuitry and is operable for adjusting a level of a reference signal based on attribute data associated with the battery pack and a difference between the battery voltage and the input voltage. The control switch is operable for passing a battery current flowing through the battery. The current regulation circuitry is coupled to the control circuit and the control switch, and is operable for controlling the control switch to regulate the battery current according to the reference signal.
1. A battery system comprising:
a plurality of input terminals coupled to a same terminal, and connectable to a plurality of battery packs; and
a first battery pack of said battery packs coupled to a first input terminal of said input terminals, wherein said first battery pack comprises:
a control switch, coupled between a battery and said first input terminal, that passes a battery current of said battery;
current regulation circuitry, coupled to said control switch, that regulates said battery current by controlling said control switch according to a reference signal; and
a control circuit, coupled to said current regulation circuitry, that adjusts said reference signal based on a difference between a battery voltage of said battery and an input voltage at said first input terminal.
2. The battery system of claim 1 , wherein said control circuit adjusts said reference signal based on said difference, and based on attribute data, associated with said battery back, stored in a storage unit.
3. The battery system of claim 1 , wherein said same terminal is coupled to a load, and wherein said first battery pack powers said load via said same terminal.
4. The battery system of claim 1 , wherein said same terminal is connectable to a power source, and wherein said power source charges said first battery pack via said same terminal if said power source is coupled to said same terminal.
5. The battery system of claim 1 , further comprising:
a second battery pack of said battery packs coupled to a second input terminal of said input terminals, wherein said control circuit balances said first battery pack and said second battery pack by regulating said battery current according to said reference signal.
6. The battery system of claim 1 , wherein said control circuit increases said reference signal if said difference between said battery voltage and said input voltage decreases.
7. The battery system of claim 1 , wherein said first battery pack further comprises:
a current sense element that senses said battery current, wherein said control circuit turns on said control switch if said battery current decreases below a threshold.
8. The battery system of claim 1 , wherein said current regulation circuitry comprises:
comparison circuitry that compares a sense signal indicative of said battery current with said reference signal to generate a comparison result,
wherein said control switch is controlled according to said comparison result.
9. The battery system of claim 1 , wherein said current regulation circuitry comprises:
comparison circuitry that compares a sense signal indicative of said battery current with said reference signal to generate a comparison result; and
current generating circuitry, coupled to said comparison circuitry, that generates a control current to a control terminal of said control switch to adjust said battery current to have a target average level, wherein said current generating circuitry comprises:
a current source that generates a preset current to charge said control terminal; and
a current regulator, coupled to said current source, that sinks at least a portion of said preset current to regulate said control current according to said comparison result.
10. The battery system of claim 9 , wherein said current regulator comprises a first switch, coupled to said control terminal, that passes a sink current to sink at least a portion of said preset current under control of a regulation signal, and wherein said comparison circuitry comprises an amplifier that generates a compensation current, according to a difference between said sense signal and said reference signal, to charge or discharge a compensation capacitor, coupled to said first switch, to control said regulation signal.
11. The battery system of claim 10 , wherein said amplifier reduces said sink current if said sense signal is less than said reference signal, increases said sink current if said sense signal is greater than said reference signal, and maintains said sink current at a level of said preset current thereby maintaining said sense signal at a level of said reference signal.
12. A method comprising:
passing a battery current of a battery in a first battery pack, using a control switch coupled between said battery and an input terminal of said first battery pack;
regulating said battery current by controlling said control switch according to a reference signal; and
adjusting said reference signal based on a difference between a battery voltage of said battery and an input voltage at said input terminal.
13. The method of claim 12 , further comprising:
adjusting said reference signal based on attribute data, associated with said battery back, stored in a storage unit.
14. The method of claim 12 , further comprising:
balancing said first battery pack and a second battery pack by regulating said battery current according to said reference signal, wherein said second battery pack is coupled to said input terminal.
15. The method of claim 12 , further comprising:
increasing said reference signal if said difference between said battery voltage and said input voltage decreases.
16. A battery pack comprising:
an input terminal connectable to a battery system;
a battery coupled to said input terminal through a control switch;
current regulation circuitry, coupled to said control switch, that regulates a battery current of said battery by controlling said control switch according to a reference signal; and
a control circuit, coupled to said current regulation circuitry, that adjusts said reference signal based on a difference between a battery voltage of said battery and an input voltage at said input terminal.
17. The battery pack of claim 16 , wherein said control circuit adjusts said reference signal based on said difference, and based on attribute data, associated with said battery back, stored in a storage unit.
18. The battery pack of claim 16 , wherein said control circuit increases said reference signal if said difference between said battery voltage and said input voltage decreases.
19. The battery pack of claim 16 , wherein said first battery pack further comprises:
a current sense element that senses said battery current, wherein said control circuit turns on said control switch if said battery current decreases below a threshold.
20. The battery pack of claim 16 , wherein said current regulation circuitry comprises:
comparison circuitry that compares a sense signal indicative of said battery current with said reference signal to generate a comparison result; and
current generating circuitry, coupled to said comparison circuitry, that generates a control current to a control terminal of said control switch to adjust said battery current to have a target average level, wherein said current generating circuitry comprises:
a current source that generates a preset current to charge said control terminal; and
a current regulator, coupled to said current source, that sinks at least a portion of said preset current to regulate said control current according to said comparison result.