Configuration, frequency registers generating power from motor in supply-loss event

Patent metadata

Field	Value
Publication number	US-9893659-B2
Application number	US-201615019326-A
Country	US
Kind code	B2
Filing date	Feb 9, 2016
Priority date	Feb 9, 2015
Publication date	Feb 13, 2018
Grant date	Feb 13, 2018

Abstract

A circuit includes a driver circuit having a high side switch device and a low side switch device coupled to a load voltage node and a motor winding output. A controller operates the high side switch device and the low side switch device. The controller operates in a normal mode to supply current to the motor winding output for driving a motor winding when an external power supply is available to supply the load voltage node. In response to detecting a loss of the external power supply, the controller operates the high side switch device and the low side switch device in a boost mode to utilize a back electromotive force (BEMF) voltage from the motor winding to supply current to the load voltage node.

First claim

What is claimed is:

1. A circuit comprising:
a driver circuit having a high side switch device and a low side switch device coupled to a load voltage node and a motor winding output; and
a controller to operate the high side switch device and the low side switch device, the controller operates in a normal mode to supply current to the motor winding output for driving a motor winding when an external power supply is available to supply electrical power to the load voltage node;
in response to detecting a loss of the external power supply, the controller operates the high side switch device and the low side switch device in a boost mode to utilize a back electromotive force (BEMF) voltage from the motor winding to supply current to the load voltage node; and
the controller including a configuration register to control the switching of the high side switch device and the low side switch device, the configuration register including a frequency register to control the pulse width modulated frequency applied to the high side switch device and the low side switch device.

2. The circuit of claim 1 , in which the controller receives voltage feedback from the load voltage node or current feedback from the motor to operate the low side switch device and the high side switch device in the boost mode.

3. The circuit of claim 1 , including an isolation switch operated by the controller to disconnect the external power supply from the load voltage node in response to detecting the loss of the external power supply.

4. The circuit of claim 3 , in which the controller includes a mode detector that generates a power supply loss signal if the external power supply falls below a predetermined threshold, the power supply loss signal employed to control the isolation switch and to switch the controller into the boost mode.

5. The circuit of claim 1 , in which the configuration register includes a slope register to select a slope of voltage at the load voltage node with respect to a duty cycle of the high side switch device and the low side switch device.

6. The circuit of claim 1 , in which the configuration register includes a duty cycle register to select a duty cycle of the high side switch device and the low side switch device based on the magnitude of the voltage at the load voltage node.

7. The circuit of claim 6 , in which the duty cycle register specifies a load voltage value where the boost mode terminates and synchronous rectification is provided by the high side switch device and the low side switch device to drive the load voltage node.

8. The circuit of claim 6 , in which the configuration register includes a maximum duty cycle register to specify a maximum duty cycle of pulses applied to the high side switch device and the low side switch device during the boost mode.

9. The circuit of claim 1 , including a phase detector to detect the polarity of the BEMF voltage such that the controller applies pulses to the high side switch device and the low side switch device during a positive voltage period of the BEMF voltage.

10. A system comprising:
a driver circuit having a plurality of switch devices coupled to a load voltage input and a plurality of motor winding outputs;
an isolation switch to couple an external supply voltage to the load voltage input during a normal mode and to decouple the external supply voltage from the load voltage input during a supply-loss event of the external supply voltage;
a controller to operate the plurality of switch devices and the isolation switch, the controller operates in the normal mode to supply current to the plurality of motor winding outputs for driving a plurality of motor windings when the external supply voltage is available to supply electrical power to the load voltage input, in response to detecting a loss of the external supply voltage, the controller decouples the external supply voltage via the isolation switch and operates the plurality of switch devices in a boost mode to utilize a back electromotive force (BEMF) voltage from the motor windings to supply current to the load voltage input, the boost mode controlling a duty cycle of switch pulses applied to the plurality of switch devices to boost the load voltage input after the supply-loss event; and
the controller including a configuration register to control the switching of the plurality of switch devices, the configuration register including a frequency register to control the pulse width modulated frequency applied to the plurality of switch devices.

11. The system of claim 10 , including a brushless direct current motor having a plurality of phases that are pulsed via the driver circuit by the controller in the normal mode and the boost mode.

12. The system of claim 10 , in which the configuration register includes a slope register to select a slope of the voltage at the load voltage input with respect to a duty cycle of the plurality of switch devices during the boost mode.

13. The system of claim 12 , in which the configuration register includes a duty cycle register to select the duty cycle of the plurality of switch devices based on the magnitude of the voltage at the load voltage input during the boost mode.

14. The system of claim 13 , in which the duty cycle register specifies a load voltage value where the boost mode terminates and synchronous rectification is provided by the plurality of switch devices to drive the load voltage.

15. A method comprising:
controlling at least one switch device to supply electrical power to windings of a motor from an external supply that is available to supply the electrical power for the motor and a load;
monitoring the electrical power for a supply-loss event; and
in response to detecting the supply-loss event, controlling a duty cycle of the at least one switch device to operate in a boost mode using electrical power from the windings of the motor to control the electrical power during a selected portion of the supply-loss event; and
in response to voltage at an input coupled to the at least one switch and the load and the motor reaching a predetermined threshold during the supply-loss event, terminating the boost mode and initiating synchronous rectification of a back electromotive force (BEMF) voltage from the motor to drive the load.

16. The method of claim 15 , including changing the duty cycle of the at least one switch device based on current feedback received from the motor during the supply-loss event.

17. The method of claim 16 , including monitoring the peak current of the motor with a current sense resistor or a sense transistor device and controlling the duty cycle such that the output current from the motor is about one half of the monitored peak current.

Assignees

• Texas Instruments Inc

Inventors

• Oh Seil
• Tran Tuan V
• Street David R
• Luebbe Juergen
• An Quang Dieu
• Rote John K

Classifications

• H02P3/14

  by regenerative braking · CPC title

• H02P6/182

  using back-emf in windings · CPC title

• H02P6/24 Primary

  Arrangements for stopping · CPC title

• H02P3/18

  for stopping or slowing an AC motor · CPC title