OPTIMIZED CHARGING APPARATUS AND METHODS

• US 20160064957A1
• Filed: 08/25/2015
• Published: 03/03/2016
• Est. Priority Date: 08/29/2014
• Status: Active Grant

• Current Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Original Assignee: Fairchild Semiconductor Corporation (ON Semiconductor Corporation)
• Inventors: Card, Robert A., Lam, Ming Chuen Alvan
• Granted Patent: US 10,090,695 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02J 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence
• CPC Class Codes: H02J 7/007 Regulation of charging or discharging current or voltage
• CPC Class Codes: H02J 7/00711 with introduction of pulses during the charging process

Abstract

This document discusses, among other things, apparatus and methods to optimize charging of a battery, including providing a first charge profile configured to provide charge current pulses to a battery in a plurality of steps. In the first charge profile, the charge current pulses can be stepped down in the plurality of steps using a comparison of a terminal voltage of the battery to a clamp voltage. When the terminal voltage meets or exceeds the clamp voltage, a high time current of the charge current pulse can be decreased and the clamp voltage can be increased before providing a subsequent charge current pulse.

Claims

1. An optimized charging apparatus, comprising:

a charge circuit configured to provide a plurality of charge current pulses to a battery in a first charge profile, the charge current pulses having a high time current and a low time current;

a control circuit configured to receive a terminal voltage of the battery and to, in the first charge profile, step down the high time current in a plurality of steps using a comparison of the terminal voltage to a clamp voltage,

wherein, in the first charge profile, if the terminal voltage is greater than or equal to the clamp voltage, the control circuit is configured to decrease the high time current and increase the clamp voltage.

2. The optimized charging apparatus of claim 1, wherein the control circuit is configured to step down the high time current from an initial high time current in a plurality of steps until the high time current is less than or equal to a first threshold.

3. The optimized charging apparatus of claim 2, wherein, if the high time current is less than or equal to the first threshold, the charge circuit is configured to provide a plurality of charge current pulses to the battery in a second charge profile, including a pulse-only charge profile, that does not include the plurality of steps of the first charge profile.

4. The optimized charging apparatus of claim 3, wherein the control circuit is configured to decrease the high time current in the second charge profile using the terminal voltage and a maximum clamp voltage until the high time current is less than or equal to a second threshold.

5. The optimized charging apparatus of claim 4, wherein, if the high time current is less than or equal to the second threshold, the charge circuit is configured to provide a current to the battery in a third charge profile to maintain a constant voltage at the battery, and

wherein the control circuit is configured to decrease the current provided to the battery in the third charge profile using the terminal voltage and the maximum clamp voltage until the current is less than or equal to a third threshold.

6. The optimized charging apparatus of claim 1, wherein, if the terminal voltage is greater than or equal to the clamp voltage, the charge circuit is configured to provide a discharge current pulse to the battery prior to a subsequent charge current pulse.

7. The optimized charging apparatus of claim 1, wherein, at each step, the control circuit is configured to decrease the high time current by a step current and to increase the clamp voltage by a step voltage, and

wherein each of the plurality of steps in the first charge profile includes a plurality of charge current pulses having equal high time current.

8. The optimized charging apparatus of claim 7, wherein the step current and the step voltage are fixed amounts.

9. The optimized charging apparatus of claim 1, wherein the plurality of steps includes 16 steps, and wherein the number of charge current pulses in each step is determined in response to the comparison of the terminal voltage to the clamp voltage.

10. The optimized charging apparatus of claim 1, wherein the plurality of charge current pulses in the first charge profile have a set duty cycle and period.

11. An optimized charging method, comprising:

providing a plurality of charge current pulses to a battery in a first charge profile, the charge current pulses having a high time current and a low time current; and

stepping down, in the first charge profile, the high time current in a plurality of steps using a comparison of a terminal voltage of the battery to a clamp voltage,

wherein the stepping down the high time current includes;

providing a first charge current pulse to the battery;

comparing the terminal voltage to a clamp voltage; and

if the terminal voltage is greater than or equal to the clamp voltage,

decreasing the high time current and increasing the clamp voltage.

12. The optimized charging method of claim 11, wherein, if the terminal voltage is greater than or equal to the clamp voltage, the stepping down the high time current includes:

providing a second charge current pulse to the battery using the decreased high time current; and

after providing the second charge current pulse to the battery, comparing the terminal voltage to the increased clamp voltage.

13. The optimized charging method of claim 11, wherein the stepping down the high time current in the first charge profile includes stepping down the first charge profile from an initial high time current in a plurality of steps until the high time current is less than or equal to a first threshold.

14. The optimized charging method of claim 13, including:

providing a plurality of charge current pulses to the battery in a second charge profile after the high time current is less than or equal to the first threshold, and

wherein the second charge profile is a pulse-only charge profile that does not include the plurality of steps of the first charge profile.

15. The optimized charging method of claim 14, including:

decreasing the high time current in the second charge profile using the terminal voltage and a maximum clamp voltage until the high time current is less than or equal to a second threshold.

16. The optimized charging method of claim 15, including:

providing a current to the battery in a third charge profile configured to maintain a constant voltage at the battery after the high time current is less than or equal to the second threshold; and

decreasing the current provided to the battery in the third charge profile using the terminal voltage and the maximum clamp voltage until the current is less than or equal to a third threshold.

17. The optimized charging method of claim 11, including:

providing a discharge current pulse to the battery prior to stepping down the high time current in the first charge profile.

18. The optimized charging method of claim 11, wherein the stepping down the high time current in the first charge profile includes, at each of the plurality of steps, decreasing the high time current by a step current and increasing the clamp voltage by a step voltage, and

wherein each of the plurality of steps in the first charge profile includes a plurality of charge current pulses having equal high time current.

19. The optimized charging method of claim 18, wherein the step current and the step voltage are fixed amounts.

20. The optimized charging method of claim 11, wherein the plurality of steps includes 16 steps, and wherein the number of charge current pulses in each step is determined in response to the comparing the terminal voltage to the clamp voltage.