Controller for multi-output single magnetic component converter with independent regulation of constant current and constant voltage outputs

Patent metadata

Field	Value
Publication number	US-10277136-B2
Application number	US-201715607075-A
Country	US
Kind code	B2
Filing date	May 26, 2017
Priority date	Dec 1, 2016
Publication date	Apr 30, 2019
Grant date	Apr 30, 2019

Abstract

A power converter includes a primary winding and multiple output windings to provide multiple independently controlled and regulated outputs with a common return line. The outputs are coupled to independently regulate constant current, constant voltage, or both constant current and constant voltage outputs. A secondary control block is coupled to control a synchronous rectifier switch coupled to the common return line to synchronize switching with a primary side power switch to provide complementary conduction of the primary winding and the multiple output windings. A plurality of controlled power pulse switches is coupled to the multiple output windings. A request of a power pulse from each of the outputs is transferred through the secondary control block to a primary switch control block to turn on the primary side power switch to transfer a power pulse to the multiple output windings and through controlled power pulse switches to the outputs.

First claim

We claim:

1. A power converter, comprising:
a single power conversion magnetic element having a primary winding coupled to an input of the power converter, and multiple output windings, wherein each one of the multiple output windings is coupled to provide an independently controlled and regulated output in response to feedback signals received from each of the independently controlled and regulated outputs demanding power, wherein the multiple output windings are electrically connected together with a common return line for all of the independently controlled and regulated outputs;
wherein regulated outputs are coupled to independently regulate constant current outputs, or constant voltage outputs, or both constant current loads and constant voltage outputs;
a primary side power switch coupled to the primary winding of the single power conversion magnetic element;
a primary switch control block coupled to control the primary side power switch to transfer energy pulses from input of the power converter to the multiple output windings;
a synchronous rectifier switch coupled to the common return line or multiple synchronous rectifier switches coupled to some or all of the return lines of the output windings;
a secondary control block coupled to control the synchronous rectifier switch to synchronize switching with the primary side power switch to provide complementary conduction of the primary winding and the multiple output windings;
a plurality of controlled energy pulse switches coupled to the multiple output windings such that the multiple output windings are coupled through the plurality of controlled energy pulse switches to the independently controlled and regulated outputs, wherein a request of an energy pulse from each of the independently controlled and regulated outputs is transferred through the secondary control block to the primary switch control block to turn on the primary side power switch to transfer the energy pulse to the multiple output windings and through controlled energy pulse switches to the independently controlled and regulated outputs; and
a multi-output control block comprising an interface to secondary control block coupled to interface and exchange signals with the secondary control block, wherein the interface to secondary control block is coupled to receive an acknowledge signal from the secondary control block endorsing receipt of an energy pulse request signal and is further coupled to receive an activation signal of a synchronous rectifier (SR) and a forward control (FWC) signal to be transferred to the multi-output control block to synchronize switching action between the primary side power switch and a secondary switch.

2. The power converter of claim 1 , wherein the multiple output windings are electrically connected together in series with the common return line for all of the independently controlled and regulated outputs.

3. The power converter of claim 1 , wherein the multiple output windings are coupled in a combination of series windings, parallel windings, or both series and parallel windings.

4. The power converter of claim 1 , wherein a constant current load at a constant current (CC) output comprises multiple paralleled light emitting diode (LED) strings.

5. The power converter of claim 1 , wherein the primary switch control block is coupled to be referenced to primary ground to control the switching of the primary side power switch.

6. The power converter of claim 5 , wherein the turn on of the primary side power switch is in response to receiving the request of the energy pulse from the secondary control block, and wherein a turn off of the primary side power switch is determined based on a ramp time modulation (RTM) engine and when a primary current pulse reaches a peak current limit.

7. The power converter of claim 6 , wherein the secondary control block is coupled to be referenced to a secondary ground to drive the synchronous rectifier switch coupled to the common return line.

8. The power converter of claim 7 , wherein the secondary control block is coupled to generate request pulses to the primary switch control block through a galvanic isolation link.

9. The power converter of claim 8 , wherein the galvanic isolation link is a magnetic/inductive link.

10. The power converter of claim 8 , wherein the primary switch control block is coupled to generate a switching drive pulse in response to the request pulse received from secondary control block.

11. The power converter of claim 1 , wherein the multi-output control block is coupled to regulate all the independently controlled and regulated outputs that are regulated to have a constant voltage or a constant current in response to respective feedback signals and power demands, wherein the multi-output control block includes a multi-output signal process and interface control block.

12. The power converter of claim 11 , further comprising a current sharing and dimming control block coupled to control voltage across a constant current output coupled to LED strings and regulate a total current in the constant current output, and wherein the current sharing block is further coupled to equalize currents in the LED strings.

13. The power converter of claim 12 , wherein the current sharing and dimming control block sets a reference for an output voltage on the LED strings and wherein the reference is determined such that a minimum voltage drop over current sources included in the current sharing and dimming control block is provided to accurately control the currents in the LED strings in order to provide sufficient voltage over the current sources to accurately control the currents in the LED strings.

14. The power converter of claim 13 , wherein the current sharing and dimming control block includes a dimming function of the LED strings by an analog linear control of current in each LED string.

15. The power converter of claim 13 , wherein the current sharing and dimming control block includes a dimming function of the LED strings comprising a PWM dimming performed by PWM control of switches coupled in series with the current sources in each LED string.

16. The power converter of claim 15 , wherein the PWM dimming is performed by in-phase dimming of the LED strings.

17. The power converter of claim 15 , wherein the PWM dimming is performed by phase-shifted dimming of the LED strings.

18. The power converter of claim 15 , wherein a capacitor included in the current sharing and dimming control block is coupled to provide a control voltage as a reference to regulate a voltage on an anode of the LED strings.

19. The power converter of claim 18 , wherein the capacitor is coupled through a series switch included in the current and dimming control block controlled by a PWM signal; and wherein, the capacitor is charged during each on-time of the LED strings, and wherein charge in the capacitor is maintained during each off-time of the LED strings.

20. The power converter of claim 18 wherein, when the LED strings are on, a voltage on the current sources is coupled to be compared to a predefined reference voltage to control the control voltage provided by the capacitor.

21. The power converter of claim 20 wherein, the control voltage provided by the capacitor is coupled to increase during on-times of the LED strings when the control voltage provided by the capacitor is below a minimum voltage for the current sources and when the voltage on the current sources is greater than the predefined reference voltage, the cont

Assignees

• Power Integrations Inc

Inventors

• Werner Antonius Jacobus Johannes
• Waterson Matthew David
• Jiang Yuncong Alex
• Saint-Pierre Roland Sylvere

Classifications

• H05B45/10 Primary

  Controlling the intensity of the light · CPC title

• H05B45/46

  having LEDs disposed in parallel lines · CPC title

• H02M3/33592

  having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer · CPC title

• H02M3/33561 Primary

  having more than one ouput with independent control · CPC title

• H02M1/08

  Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters · CPC title