RMS RESPONDING VOLTAGE CONVERTER FOR LED LIGHTS

• US 20130320880A1
• Filed: 05/16/2013
• Published: 12/05/2013
• Est. Priority Date: 05/16/2012
• Status: Abandoned Application

• Current Assignee: Microchip Technology Incorporated
• Original Assignee: Microchip Technology Incorporated
• Inventors: Walker, James T.
• Application Number:
  US13/896,240
• Publication Number:
  US 20130320880A1
• Time in Patent Office: Days
• US Class Current: 315/294
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]

Abstract

An RMS responding voltage converter for LED lights is disclosed.

Claims

1. A voltage converter for generating a high power factor voltage, comprising:

a bridge rectifier for rectifying alternating current from a power source;

an inductor coupled to the bridge rectifier;

a switch for applying an input voltage to the inductor; and

an oscillator for controlling the switch;

wherein the voltage converter outputs a voltage with a high power factor.

2. A voltage converter for driving a plurality of light emitting diodes, comprising:

a bridge rectifier for rectifying alternating current from a power source;

a peak detection circuit coupled to the bridge rectifier for identifying peaks in an output of the bridge rectifier;

an inductor comprising a first end and a second end, wherein the first end is coupled to the bridge rectifier and the second end provides an output voltage for driving a plurality of light emitting diodes;

a switch comprising a gate, a first terminal, and a second terminal, wherein the first terminal is coupled to the inductor;

a resistor coupled to the second terminal; and

a control circuit coupled to the gate for controlling the switch, wherein the control circuit comprises;

an oscillator;

a pulse generator that receives a signal from the oscillator and a signal from a shaper circuit, wherein the shaper circuit receives a signal from the peak detection circuit;

control logic that receives a signal from the pulse generator; and

a gate driver that receives a signal from the control logic, wherein the gate driver is coupled to the gate.

3. The voltage converter of claim 2, further comprising:

one or more noise filters coupled to the bridge rectifier.

4. The voltage converter of claim 2, further comprising:

a trim circuit coupled to the oscillator for adjusting a frequency of the oscillator and a width of the pulse generator.

5. The voltage converter of claim 4, wherein the trim circuit comprises a plurality of fusible links.

6. The voltage converter of claim 2, further comprising:

a charge pump for providing a voltage used by one or more components of the voltage converter.

7. The voltage converter of claim 2, further comprising:

an over voltage protection detector coupled to the control logic.

8. The voltage converter of claim 2, further comprising:

a digital dimmer control circuit coupled to the pulse generator for adjusting the period in which the gate is activated.

9. The voltage converter of claim 2, further comprising:

a shunt regulator for controlling the voltage applied to the various control circuits used to implement the voltage converter.

10. The voltage converter of claim 2, further comprising:

a current sensing circuit for detecting when said switch draws excessive current and provided with the ability to limit said current by turning off said switch.

11. The voltage converter of claim 2, further comprising:

a current sensing circuit for detecting when said switch draws less than a predetermined value of current during its conduction time, and which causes said switch to remain in a conducting state until said current satisfies the predetermined current value.

12. The voltage converter of claim 2, further comprising:

a logic control block with a multiplicity of inputs for detecting if said power converter has more than one voltage input, and outputting control signals determined by the combination of inputs in use.

13. The voltage converter of claim 2, further comprising:

a digital to analog voltage converter for generating an additional control voltage for said pulse generator determined by the combination of voltage inputs in use.

14. The voltage converter of claim 2, further comprising:

control logic arranged to cause the input impedance presented to the input voltage source to be substantially resistive.

15. The voltage converter of claim 2, further comprising:

a chosen control function for said shaper circuit such that the power output of said power converter is substantially constant when the input voltage to said power converter is varied over a range of values.

16. The voltage converter of claim 3, further comprising:

noise filter means which incorporate non-linear circuit elements.

17. The voltage converter of claim 2, further comprising:

signal processing means which incorporate non-linear circuit elements.

18. The voltage converter of claim 2, further comprising:

a timer circuit for increasing the minimum current conduction required in said switch during a predetermined time after the said power converter input voltage goes to zero.

19. The voltage converter of claim 2, further comprising:

a leading edge blanking circuit for filtering a sense voltage representing the conduction current flowing through said switch.

20. The voltage converter of claim 7, further comprising:

hysteresis circuits provided for said over voltage circuit.

21. The voltage converter of claim 4, further comprising:

trim circuits made such that the trim operation may be performed by electrical means after said power converter control circuit is placed in its package.

22. The voltage converter of claim 2, further comprising:

trim circuits arranged such that the operating parameters of said power converter may be electrically adjusted more than one time.