Driver with open output protection

Patent metadata

Field	Value
Publication number	US-2016119987-A1
Application number	US-201514672721-A
Country	US
Kind code	A1
Filing date	Mar 30, 2015
Priority date	Oct 24, 2014
Publication date	Apr 28, 2016
Grant date	—

Abstract

A load driver for driving a load and an LED module are disclosed. In one embodiment, the load driver comprises a converter circuit comprising a controllable switching element configured to be turned on and off and to perform power factor correction for power from a power supply to the load, wherein a control terminal of the controllable switching element is configured for receiving a startup current via the two output terminals, the controllable switching element configured to be turned on by the startup current. The converter circuit further comprises a first inductor, coupled to the power supply at a first end, and to ground at a second end via the controllable switching element, wherein a first one of the output terminals connects to a second end of the first inductor via a diode forwarded from the first inductor, a second one of the output terminals is coupled to the first end of the first inductor.

First claim

What is claimed is:

1 . A load driver for driving a load, the load driver comprising:
two output terminals for coupling to the load; and a converter circuit comprising:
a controllable switching element configured to be turned on and off and to perform power factor correction for power from a power supply to the load, wherein a control terminal of the controllable switching element is coupled to and in series with the two output terminals and is configured for receiving a startup current via the two output terminals, the controllable switching element configured to be turned on by said startup current;
wherein the converter circuit is a buck-boost converter and further comprises:
a first inductor, coupled to the power supply at a first end, and to ground at a second end via the controllable switching element;
wherein a first one of the output terminals connects to a second end of the first inductor via a diode forwarded from the first inductor, a second one of the output terminals is coupled to the first end of the first inductor.

2 . The load driver according to claim 1 , wherein the second one of the output terminals connects to the first end of said first inductor via a diode forwarded from the second one of the output terminals.

3 . The load driver according to claim 1 , wherein the control terminal of the controllable switching element connects to the second one of the output terminals.

4 . The load driver according to claim 1 , further comprising a startup resistor between the control terminal and the two output terminals.

5 . The load driver according to claim 1 , further comprising:
an output buffer capacitor across the first one of the output terminals and the first end of the first inductor.

6 . The load driver according to claim 1 , wherein the switching element comprises a transistor and a base of the transistor is in series with the two output terminals, or
the switching element comprises a MOSFET and a gate of the MOSFET is in series with the two output terminals.

7 . The load driver according to claim 6 , wherein the converter circuit further comprises a third inductor electromagnetically coupled to the first inductor and coupled to the controllable switching element, the third inductor is adapted to being inductive of a high voltage in response to an over voltage on the first inductor and to turn off the switching element.

8 . The load driver according to claim 7 , wherein the load driver further comprises:
a switching unit between the control terminal of the controllable switching element and the ground, adapted to draw current from the control terminal of the controllable switching element to turn the controllable switching element off; wherein the third inductor connects to a control terminal of the switching unit and applies the high voltage thereupon to turn on the switching unit.

9 . The load driver according to claim 8 , wherein the converter circuit is a RCC circuit with a second inductor electromagnetically coupled to the first inductor and coupled to the controllable switching element, and a current sensing resistor coupled between the controllable switching element and the ground.

10 . An LED module, comprising:
a load driver according to claim 1 ; and at least one LED coupled between the two output terminals such that the control terminal of the controllable switching element is in series with the LED.

11 . The LED module according to claim 10 , wherein the second one of the output terminals connects to the first end of said first inductor via a diode forwarded from the second one of the output terminals.

12 . The LED module according to claim 10 , wherein the control terminal of the controllable switching element connects to the second one of the output terminals.

13 . The LED module according to claim 10 , further comprising a startup resistor between the control terminal and the two output terminals.

14 . The LED module according to claim 10 , further comprising an output buffer capacitor across the first one of the output terminals and the first end of the first inductor.

15 . The LED module according to claim 10 , wherein the switching element comprises a transistor and a base of the transistor is in series with the two output terminals, or
the switching element comprises a MOSFET and a gate of the MOSFET is in series with the two output terminals.

16 . The LED module according to claim 15 , wherein the converter circuit further comprises a third inductor electromagnetically coupled to the first inductor and coupled to the controllable switching element, the third inductor is adapted to being inductive of a high voltage in response to an over voltage on the first inductor and to turn off the switching element.

17 . The LED module according to claim 16 , wherein the load driver further comprises:
a switching unit between the control terminal of the controllable switching element and the ground, adapted to draw current from the control terminal of the controllable switching element to turn the controllable switching element off; wherein the third inductor connects to a control terminal of the switching unit and applies the high voltage thereupon to turn on the switching unit.

18 . The LED module according to claim 17 , wherein the converter circuit is a RCC circuit with a second inductor electromagnetically coupled to the first inductor and coupled to the controllable switching element, and a current sensing resistor coupled between the controllable switching element and the ground.

Assignees

• Koninkl Philips Nv

Inventors

• Chen Zhi Quan
• Li Duo L
• Li Kang
• Ma Matt J
• Zhang Hui
• Claessens Dennis Johannes Antonius

Classifications

• H02M3/1563 Primary

  without using an external clock (H02M3/158 takes precedence) · CPC title

• H02M1/36

  Means for starting or stopping converters · CPC title

• H05B45/50

  responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits · CPC title

• H02M3/155

  using semiconductor devices only · CPC title

• H02M1/42

  Circuits or arrangements for compensating for or adjusting power factor in converters or inverters · CPC title