BATTERY CHARGING CIRCUIT

• US 20090085524A1
• Filed: 09/25/2008
• Published: 04/02/2009
• Est. Priority Date: 09/27/2007
• Status: Active Grant

• Current Assignee: Pulsetech Products Corporation
• Original Assignee: Pulsetech Products Corporation
• Inventors: Sykes, David Lee, Smith, Pete Ward, Calcote, Clyde Ray, Huffman, James Earl
• Granted Patent: US 8,269,465 B2
• Time in Patent Office: Days
• US Class Current: 320/139
• CPC Class Codes: H02J 7/00711 with introduction of pulses during the charging process

Abstract

A circuit charges and maintains a battery. The circuit includes a microprocessor for receiving a current sense signal and a voltage sense signal. The microprocessor generates control signals for selectively operating the circuit in a charging mode and in a maintenance mode. The circuit includes a current sense circuit for measuring the battery'"'"'s current consumption and generating the current sense signal responsive to the measured current consumption. The circuit includes a voltage sense circuit for measuring the battery'"'"'s voltage and generating the voltage sense signal responsive to the measured battery voltage. The circuit includes a waveform generator circuit for receiving the control signals, and operating in response thereto to apply a charging signal to the battery when in the charging mode and to deactivate the charging signal when in the maintenance mode. The charging signal has an oscillating triangular waveform superimposed on a DC bias signal.

Claims

1. A circuit for charging a battery, comprising:

a microprocessor for receiving a current sense signal and a voltage sense signal, the microprocessor generating control signals for selectively operating the circuit in a charging mode and a maintenance mode;

a current sense circuit for measuring the battery'"'"'s current consumption and generating the current sense signal responsive to the measured current consumption;

a voltage sense circuit for measuring the battery'"'"'s voltage and generating the voltage sense signal responsive to the measured battery voltage; and

a waveform generator circuit for receiving the control signals, and operating in response thereto to apply a charging signal to the battery when in the charging mode and to deactivate the charging signal when in the maintenance mode, wherein the charging signal has an oscillating triangular waveform superimposed on a DC bias signal.

2. The circuit according to claim 1, wherein the oscillating triangular waveform is characterized by a relatively short linear rise time followed by a substantially long linear fall time.

3. The circuit according to claim 1, wherein the microprocessor operates the circuit in the charging mode if the measured battery voltage is less than a first threshold voltage.

4. The circuit according to claim 1, wherein the microprocessor operates the circuit in the maintenance mode if the measured voltage exceeds the first threshold voltage and the measured current consumption is less than a first threshold current.

5. The circuit according to claim 4, wherein, during the maintenance mode, the microprocessor applies the oscillating triangular waveform superimposed on the DC bias signal if the measured voltage is less than a second threshold voltage.

6. The circuit according to claim 1, wherein the triangular waveform has a linear rise time of approximately 412 million V/sec.

7. The circuit according to claim 1, wherein the triangular waveform has a linear fall time of approximately 40 million V/sec.

8. The circuit according to claim 1, wherein the triangular waveform has a frequency between 30 KHz and 50 KHz.

9. The circuit according to claim 1, wherein the waveform generator circuit comprises:

a pulse transformer having primary and secondary windings, the primary winding to which is applied the pulse control signals;

a transistor in series with a first resistor coupled between the secondary winding and a ground; and

an R-C network formed by a second and a third resistor and a capacitor, the R-C network coupled to a base junction of the transistor to cause a slow, tapered linear pinch off of the transistor'"'"'s conductance to enable the circuit to output the triangular waveform, the R-C network coupled to the secondary winding via a first and a second diode, respectively.

10. The circuit according to claim 9, further comprising a third diode coupling the battery to the secondary winding, the battery being charged by the application of the triangular waveform.

11. A circuit for charging battery, comprising:

a microprocessor for receiving a current sense signal and a voltage sense signal, the microprocessor generating a first control signal and a second control signal;

a current sense circuit for measuring the battery'"'"'s current consumption and generating the current sense signal responsive to the measured current consumption;

a voltage sense circuit for measuring the battery'"'"'s voltage and generating the voltage sense signal responsive to the measured battery voltage; and

a waveform generator circuit for receiving the first and second control signals and a DC bias signal, the waveform generator circuit generating an output signal for application to the battery when in a charging mode as selected by the first and second control signals, the output signal including an oscillating triangular waveform superimposed on the DC bias signal, the waveform generator circuit deactivating the oscillating triangular waveform superimposed on the DC bias when in a maintenance mode as selected by the first and second control signals.

12. The circuit according to claim 11, wherein the oscillating triangular waveform is characterized by a relatively short linear rise time followed by a substantially long linear fall time.

13. The circuit according to claim 11, wherein the first control signal turns on an oscillator circuit and the second control signal switches in the DC bias signal when in the charging mode if the measured battery voltage is less than a first threshold voltage.

14. The circuit according to claim 11, wherein the first control signal turns OFF an oscillator circuit and switches out the DC bias signal when in the rejuvenating mode if the measured voltage exceeds a first threshold voltage and the measured current consumption is less than a first threshold current.

15. The circuit according to claim 14, wherein, during the maintenance mode, the first control signal turns ON the oscillating triangular waveform and the second control signal switches ON the DC bias signal if the measured voltage is less than a second threshold voltage.

16. The circuit according to claim 11, wherein the triangular waveform has a linear rise time of approximately 412 million V/sec.

17. The circuit according to claim 11, wherein the triangular waveform has a linear fall time of approximately 40 million V/sec.

18. The circuit according to claim 11, wherein the triangular waveform has a frequency between 30 KHz and 50 KHz.

19. The circuit according to claim 11, wherein the waveform generator circuit further comprises:

a pulse transformer having primary and secondary windings, the primary winding to which is applied the pulse control signals;

a transistor in series with a first resistor coupled between the secondary winding and the ground; and

an R-C network formed by a second and a third resistor and a capacitor, the R-C network coupled to a base junction of the transistor to cause a slow, tapered linear pinch off of the transistor'"'"'s conductance to enable the circuit to output the triangular waveform, the R-C network coupled to the secondary winding via a first and a second diode, respectively.

20. The circuit according to claim 11, further comprising a third diode coupling an external battery to the secondary winding, the external battery being charged by the application of the triangular waveform.

21. A circuit, comprising:

a current sense circuit for measuring a current consumption of a battery during charging and generating a current sense signal;

a voltage sense circuit for measuring a voltage of the battery and generating a voltage sense signal;

a signal generator for applying a signal to the battery, the signal generating comprising;

a first circuit for generating an oscillating triangular waveform; and

a second circuit for generating a DC bias signal;

a control circuit responsive to the current sense signal and the voltage sense signal;

the control circuit controlling the signal generator to apply the signal to the battery with the oscillating triangular waveform superimposed on the DC bias signal if the voltage sense signal indicates a voltage less than a first threshold, the control circuit controlling the signal generator to inhibit the oscillating triangular waveform superimposed on the DC bias signal if the voltage exceeds the first threshold and if the current sense signal indicates the current consumption is less than a second threshold.

22. The circuit according to claim 21, wherein the oscillating triangular waveform is characterized by a relatively short linear rise time followed by a substantially long linear fall time.