Dimmer detector for bleeder circuit activation

Patent metadata

Field	Value
Publication number	US-9408261-B2
Application number	US-201414246770-A
Country	US
Kind code	B2
Filing date	Apr 7, 2014
Priority date	May 7, 2013
Publication date	Aug 2, 2016
Grant date	Aug 2, 2016

Abstract

A circuit to be utilized for an LED driver bleeder activation. The circuit comprises a circuit block for timing a duration of any removed portion of a rectified line signal. The input of the circuit to be coupled to receive the phase controlled rectified line signal through a voltage divider. Comparing the divided rectified line signal with a threshold voltage and output a comparison result. A timer coupled to the comparator and responsive to the comparison result to time the duration of the removed portion of the rectified line signal and activate the bleeder activation circuitry to turn on the switching element of the bleeder to sink a controlled current from the input line.

First claim

What is claimed is:

1. A circuit for timing a duration of any removed portion of a rectified line signal, the circuit comprising:
an input to be coupled to receive the rectified line signal;
a voltage divider coupled to the input to yield a divided rectified line signal;
a first comparator coupled to compare the divided rectified line signal with a first threshold voltage and to output a comparison result; and
a timer coupled to the first comparator and responsive to the comparison result to time the duration of the removed portion of the rectified line signal.

2. The circuit of claim 1 , wherein the voltage divider is a resistor voltage divider comprising resistors configured and arranged to withstand a rectified line signal voltage.

3. The circuit of claim 1 , wherein the timer comprises a timing capacitor coupled to be charged or discharged in response to the comparison result.

4. The circuit of claim 3 , wherein the timing capacitor is coupled to be at a timing voltage at an instant that removal of the portion of the rectified line signal begins should the removed portion of the rectified line signal be a trailing edge of the rectified line signal.

5. The circuit of claim 4 , wherein the timer further comprises a second comparator coupled to compare the timing voltage on the timing capacitor with a second threshold voltage, wherein the second threshold voltage is set relative to the timing voltage so that the timing voltage on the timing capacitor only crosses the second threshold voltage if the rectified line signal is dimmed by a threshold amount.

6. The circuit of one of claim 1 , further comprising:
a diode having an anode coupled to the input; and
a supply capacitor coupled to the cathode of the diode to store a supply voltage for supplying the circuit.

Assignees

• Power Integrations Inc

Inventors

• Angeles Christian Pura
• Espino Marvin C

Classifications

• H05B45/10

  Controlling the intensity of the light · CPC title

• H05B45/3575

  by means of dummy loads or bleeder circuits, e.g. for dimmers · CPC title

• H02M7/2176

  comprising a passive stage to generate a rectified sinusoidal voltage and a controlled switching element in series between such stage and the output · CPC title

• H02M7/1557 Primary

  with automatic control of the output voltage or current · CPC title

• H05B33/0809

  Electricity · mapped topic