Wake-by-control pilot circuit for onboard battery charger

1. An on-board battery charging system for a vehicle comprising:

a charging unit including a power converter operable to convert energy supplied by an external power supply into a usable form for charging a high-voltage battery during a battery charging operation;

a controller in communication with the charging unit for monitoring and controlling the battery charging operation, the controller being further operable to detect a connection to the external power supply; and

a wake-by-control pilot circuit powered by a low-voltage power source and connected to an input side of the controller, the wake-by-control pilot circuit having an input for receiving a control pilot signal and outputting a wake-up signal pulse to wake the controller from a sleep mode at least when the external power supply exits a delayed charge mode;

wherein the wake-by-control pilot circuit includes a pulse width modulation (PWM) detector that outputs signal pulses when the control pilot signal is pulse width modulated.

2. The system of claim 1 , wherein the control pilot signal indicates a valid connection to the external power supply and a maximum current that can be drawn from an electrical power utility grid.

3. The system of claim 1 , wherein the wake-by-control pilot circuit generates the wake-up signal pulse when the control pilot signal transitions from a non-zero static DC voltage to an active PWM signal.

4. The system of claim 3 , wherein the wake-by-control pilot circuit further generates the wake-up signal pulse upon an initial detection of the control pilot signal.

5. The system of claim 1 , wherein the PWM detector includes a logic circuit having a first input for receiving the control pilot signal and a second input for receiving a delayed control pilot signal.

6. The system of claim 5 , wherein the logic circuit is an exclusive-OR gate.

7. The system of claim 1 , wherein an output from the PWM detector is zero when the control pilot signal is a static DC voltage.

8. The system of claim 1 , wherein the wake-by-control pilot circuit includes a peak detector operable to output a lower-voltage DC signal when the PWM detector outputs signal pulses.

9. The system of claim 8 , wherein the peak detector output is zero when the PWM detector output is zero.

10. The system of claim 9 , wherein the wake-by-control pilot circuit includes a rising edge detector operable to output the wake-up signal pulse upon a transition from zero to the lower-voltage DC signal at the peak detector output.

11. A wake-by-control pilot circuit for generating a wake-up signal pulse to a controller for an on-board battery charging system provided in a vehicle, the wake-by-control pilot circuit comprising:

an input for receiving a control pilot signal;

a pulse width modulation (PWM) detector that outputs signal pulses when the control pilot signal is pulse width modulated;

a peak detector connected to an output side of the PWM detector, the peak detector operable to output a lower-voltage DC signal when the PWM detector outputs signal pulses; and

an edge detector connected to an output side of the peak detector, the edge detector operable to output the wake-up signal pulse upon a transition from zero to the lower-voltage DC signal at the peak detector output.

12. The wake-by-control pilot circuit of claim 11 , wherein the control pilot signal indicates a valid connection to an external power supply and a maximum current that can be drawn from an electrical power utility grid.

13. The wake-by-control pilot circuit of claim 11 , wherein the wake-by-control pilot circuit generates the wake-up signal pulse when the control pilot signal transitions from zero to any active signal and when the control pilot signal transitions from a non-zero static DC voltage to an active PWM signal.

14. The wake-by-control pilot circuit of claim 11 , wherein the PWM detector includes a logic gate having a first input for receiving the control pilot signal and a second input for receiving a delayed control pilot signal.

15. The wake-by-control pilot circuit of claim 14 , wherein the logic gate is an exclusive-OR gate.

16. The wake-by-control pilot circuit of claim 14 , further comprising a lower-voltage power source operable to power the PWM detector.

17. An apparatus comprising:

an on-board battery charger connected to a high-voltage battery in a vehicle and operable to charge the high-voltage battery when connected to electric vehicle supply equipment (EVSE), the on-board battery charger including:

a controller operable to detect a connection to the EVSE; and

a wake-by-control pilot circuit connected to an input side of the controller, the wake-by-control pilot circuit having an input for receiving a control pilot signal from the EVSE and outputting a wake-up signal pulse to wake the controller from a sleep mode when the EVSE exits a delayed charge mode, the wake-by-control pilot circuit including a pulse width modulation (PWM) detector that outputs signal pulses when the control pilot signal is pulse width modulated.

18. The apparatus of claim 17 , wherein the wake-by-control pilot circuit further comprises:

a lower-voltage power source operable to power the PWM detector;

a peak detector connected to an output side of the PWM detector, the peak detector operable to output a lower-voltage DC signal when the PWM detector outputs signal pulses; and

an edge detector connected to an output side of the peak detector, the edge detector operable to output the wake-up signal pulse upon a transition from zero to the lower-voltage DC signal at the peak detector output.

19. The apparatus of claim 18 , wherein the wake-by-control pilot circuit generates the wake-up signal pulse when the control pilot signal transitions from zero to any active signal and when the control pilot signal transitions from a non-zero static DC voltage to an active PWM signal.