Resonant converter with phase delay control

• US 20040012985A1
• Filed: 02/28/2003
• Published: 01/22/2004
• Est. Priority Date: 12/12/2001
• Status: Active Grant

• Current Assignee: Infineon Technologies Americas Corp. (Infineon Technologies AG)
• Original Assignee: International Rectifier Corporation (Infineon Technologies AG)
• Inventors: Ribarich, Thomas J.
• Granted Patent: US 6,903,949 B2
• Time in Patent Office: Days
• US Class Current: 363/21.02
• CPC Class Codes: H02M 3/01 Resonant DC/DC converters
• CPC Class Codes: H02M 3/33571 Half-bridge at primary side of an isolation transformer
• CPC Class Codes: H02M 7/523 with LC-resonance circuit in the main circuit
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A phase delay control for a power converter operates with a phase locked loop and current sense feedback to provide improved control stability and dynamic output range. The phase lock loop includes a voltage controlled oscillator that is controlled based on an error signal derived from a phase of the power converter output. The error signal applied to the voltage controlled oscillator produces a shift in switching frequency for the converter to drive the error to zero. The power converter includes an LCC resonant circuit to manipulate resonant electrical energy to improve switching speed and power density.

Claims

1. A power converter controller for controlling a resonant power converter, comprising:

current sense circuitry for detecting a phase of a power converter feedback signal and providing a related phase angle signal;

a phase locked loop circuit for controlling a switching frequency of the power converter, the phase angle signal being applied to an input of the phase locked loop;

a phase angle error signal generated in the phase locked loop in relation to a reference phase angle and the phase angle signal;

a voltage controlled oscillator in the phase locked loop for adjusting a switching frequency of the resonant power converter, the phase angle error signal being applied to an input of the voltage controlled oscillator;

switch output circuitry coupled to the phase lock loop for controlling switching of power switches in the resonant power converter; and

the power converter feedback signal being influenced by switching the power switches in the resonant converter, such that a power output of the resonant power converter is controllable through phase adjustment provided by the phase locked loop.

2. A power converter controller according to claim 1, wherein the power converter feedback signal comprises a voltage across a resistor coupled to one of the power switches.

3. A power converter controller according to claim 1, wherein the resonant power converter has a resonant frequency, and the switching frequency is equal to or greater than the resonant frequency.

4. A power converter controller according to claim 1, further comprising a fault signal provided by the current sense circuitry for enunciating faults to permit the resonant power converter to be placed in a safety mode of operation.

5. A power converter controller according to claim 1, wherein the controller is implemented on an IC.

6. A power converter controller according to claim 1, further comprising selection circuitry for selectively enabling or disabling controller functions.

7. A power converter controller according to claim 1, wherein the current sense circuitry provides an indication of a zero crossing for a switch voltage.

8. A power converter controller according to claim 1, further comprising a blanking circuit for masking the phase angle signal for a specified period of time.

9. A power converter controller according to claim 8, wherein the specified period of time is about 400 nanoseconds.

10. A power converter controller according to claim 1, wherein the phase angle control is operable in a range of from about 0 to about −

90°

.

11. A power converter controller according to claim 1, wherein the resonant power converter includes an LCC circuit.

12. A switching power converter having a regulated power output through the operation of power switches in a half bridge configuration, wherein the switching of the switches is controlled by the power converter controller according to claim 1.

13. A power converter controller according to claim 1, further comprising programmable inputs for determining a minimum phase shift reference and a maximum phase shift.

14. A power converter controller according to claim 2, wherein the resistor is coupled to a low side switch of a half bridge switching arrangement.

15. A power converter, comprising:

a resonant circuit for storing electrical energy;

a half bridge switching arrangement coupled to the resonant circuit for controlling transfer of the electrical energy into and out of the resonant circuit;

a controller coupled to the half bridge circuit for controlling switching of switches in the half bridge circuit;

a current sensing device coupled to the half bridge circuit and to the controller for providing a current sense signal to the controller;

a current sense signal circuit in the controller for providing a phase angle signal based on the current sense signal; and

a phase locked loop in the controller operable to accept the phase angle signal and provide a switching control for switching the switches in the half bridge circuit such that a phase of the electrical energy in the resonant circuit is adjustable towards a reference phase.

16. A power converter according to claim 15, wherein the phase locked loop further comprises a voltage controlled oscillator to provide a variable oscillatory output for adjusting a phase in the resonant circuit.

17. A power converter according to claim 15, wherein the current sensing device is a resistor, across which a voltage measurement can be taken to obtain the current sense signal.

18. A power converter according to claim 15, wherein the controller circuit is incorporated into an IC.

19. A power converter according to claim 15, further comprising a function selection circuit coupled to the controller for selectively adjusting controller functions.

20. A power converter according to claim 15, wherein the controller further comprises a current sense blanking device for masking the current sense signal for a specified time interval.

21. A method for controlling a resonant power converter with a resonant circuit through a phase delay control, comprising:

measuring a phase angle of a control output coupled to the resonant circuit;

comparing the phase angle to a reference phase angle to obtain a phase angle error signal;

applying the phase angle error signal to a phase locked loop to adjust a switching frequency through a voltage controlled oscillator in the phase locked loop; and

decreasing the phase angle error signal by adjusting the switching frequency such that the phase angle tracks the reference phase angle to control power supplied by the resonant power converter.