Low standby power control circuit for LED driver

Patent metadata

Field	Value
Publication number	US-10178720-B1
Application number	US-201815872538-A
Country	US
Kind code	B1
Filing date	Jan 16, 2018
Priority date	Jan 17, 2017
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

An LED driver is configured to minimize power consumption during standby operating modes. The LED driver includes power factor correction (PFC) and isolated DC-DC conversion stages, driven by respective first and second regulators. An auxiliary sensor detects environmental conditions for a controller which generates standby or normal operating mode signals based thereon. A low standby isolated power supply circuit receives operating mode signals and is configured: responsive to normal operating mode signals to enable the voltage regulators; responsive to standby mode signals to disable the voltage regulators, and in both modes to supply power to the controller and auxiliary sensor. Accordingly, the controller and auxiliary sensor are continuously enabled whereas the PFC and DC-DC stages of the LED driver are disabled during standby modes. Additional circuitry may selectively disconnect voltage sensing resistance networks from the LED driver for further reductions in power consumption during standby mode.

First claim

What is claimed is:

1. An LED driver comprising:
a power factor correction (PFC) stage coupled to receive input power from a DC input power stage;
an isolated DC-DC power converter stage coupled to an output of the PFC stage, and configured to provide DC current to an LED lighting load;
first and second regulators configured to provide drive signals to the PFC stage and the isolated DC-DC power converter stage, respectively;
one or more auxiliary sensors configured to detect one or more environmental conditions;
a controller coupled to receive auxiliary feedback signals from the one or more auxiliary sensors, and configured to provide standby mode signals or normal operating mode signals based on a detected environmental condition from the one or more auxiliary sensors; and
a low standby isolated power supply circuit comprising
a power converter comprising a primary side coupled to the DC input power stage and a secondary side coupled to supply power to the controller and the one or more auxiliary sensors,
a switching element coupled to the primary side of the power converter,
an input resistor coupled on a first end between the switching element and the primary side of the power converter, and
an isolation device configured responsive to the standby mode signals on a first side to disable supply power from the primary side of the power converter to the first and second regulators, and responsive to the normal operating mode signals on the first side to enable supply power from the primary side of the power converter to the first and second regulators, the isolation device having a second side coupled between a second end of the first input resistor and a gate electrode of the switching element, wherein the low standby isolated power supply circuit is configured
responsive to the normal operating mode signals to enable the first and second regulators,
responsive to the standby mode signals to disable the first and second regulators, and
in both modes to supply power to the controller and the one or more auxiliary sensors.

2. The LED driver of claim 1 , wherein the isolation device comprises an opto-coupler having a phototransistor on the first side and a diode on the second side, wherein an anode of the diode is coupled to receive the standby mode signals and the normal operating mode signals.

3. The LED driver of claim 2 , further comprising
first and second resistors coupled in series on a first end to the output of the PFC stage, and on a second end to a ground on the primary side of the DC-DC converter, wherein
a node between the first and second resistors is coupled to the first regulator as a voltage sensor; and wherein the low standby isolated power supply circuit further comprises
a second opto-coupler having a phototransistor on a first side and a diode on a second side, an anode of the diode for the second opto-coupler is coupled to receive the standby mode signals and the normal operating mode signals, and the phototransistor for the second opto-coupler is configured responsive to said standby mode signals and said normal operating mode signals to respectively disconnect and connect the first and second resistors from the bus voltage.

4. The LED driver of claim 1 , wherein one or more of the auxiliary sensors are configured to detect one or more environmental conditions representative of an occupancy state in a defined area associated with the LED load, and wherein the controller is configured to determine the occupancy state based on the detected one or more environmental conditions and generate the standby mode signals or normal operating mode signals based thereon.

5. The LED driver of claim 1 , wherein one or more of the auxiliary sensors are configured to detect one or more environmental conditions representative of ambient light in a defined area associated with the LED load, and wherein the controller is configured to compare an ambient light level with a threshold light level based on the detected one or more environmental conditions and generate the standby mode signals or normal operating mode signals based thereon.

6. A low standby isolated power supply circuit for an LED driver including an input power stage, a power factor correction (PFC) stage driven by a first regulator to provide a DC bus voltage, an isolated DC-DC power converter stage driven by a second regulator to provide DC current to an LED lighting load, one or more auxiliary sensors configured to detect one or more environmental conditions, and a controller configured to provide first or second operating mode signals based on the detected one or more environmental condition from the one or more auxiliary sensors, the low standby isolated power supply circuit comprising:
a power converter having a primary side coupled to receive input power from the DC input power stage and a secondary side coupled to supply power to the LED driver controller and the one or more auxiliary sensors;
a switching element coupled to the primary side of the power converter;
an input resistor coupled on a first end between the switch and the primary side of the power converter; and
an isolation device configured responsive to the first operating mode signals on a first side to disable supply power from the power converter to the first and second regulators, and responsive to the second operating mode signals to enable supply power from the power converter to the first and second regulators, the isolation device having a second side coupled between a second end of the first input resistor and a gate electrode of the switching element,
wherein the LED driver controller and the one or more auxiliary sensors are enabled in both of the first and second operating modes, and wherein the PFC stage and the DC-DC converter of the LED driver are enabled only in the second operating mode.

7. The low standby isolated power supply circuit of claim 6 , wherein the isolation device comprises an opto-coupler having a phototransistor on the first side and a diode on the second side, wherein an anode of the diode is coupled to receive the first and second operating mode signals.

Assignees

• Universal Lighting Tech Inc
• Universal Lighting Tech

Inventors

• Xiong Wei

Classifications

• H02M3/335

  using semiconductor devices only · CPC title

• H05B47/11

  by determining the brightness or colour temperature of ambient light · CPC title

• H05B33/0815 Primary

  Electricity · mapped topic

• H05B33/0842

  Electricity · mapped topic

• H05B37/0218

  Electricity · mapped topic