Dual output power supply
View Patent ↗A single power supply provides at least one constant voltage output and at least one constant current output. The single power supply includes two or more switching power converters, such as flyback converters, that are independently controllable based on an error signal corresponding to the associated output. Further, one or more of the switching power converters can implement such control using primary-side feedback. The switching power converters can be flyback converters. Any switching power converters included the in the single power supply can both be part of a single PCB assembly, part of a single IC package, or part of a single monolith semiconductor die.
1. A power supply circuit, comprising:
a first power converter configured to produce a constant voltage output based on an input signal, the first power converter comprises a first switch and a first switch control circuit, wherein the first switch control circuit controls the first power converter in response to a first error signal for driving the first switch; and
a second power converter configured to produce a constant current output based on the input signal, the second power converter comprises a second switch and a second switch control circuit, wherein the second switch control circuit controls the second power converter in response to a second error signal for driving the second switch, the second switch control circuit operated independent from the first switch control circuit.
2. The power supply circuit of claim 1 , wherein the first switch control circuit and the second switch control circuit are included in a single integrated circuit.
3. The power supply circuit of claim 1 , wherein the first switch control circuit and the second switch control circuit are implemented on a single monolithic semiconductor die.
4. The power supply circuit of claim 1 , wherein the first power converter and the second power converter are based on a flyback topology.
5. The power supply circuit of claim 1 , wherein the first power converter and the second power converter employ a switch control method based on primary-side feedback.
6. The power supply circuit of claim 1 , wherein the power supply circuit is included in the case of a television monitor.
7. A power supply package for controlling delivery of power from a source to a plurality of loads, comprising:
a first terminal for coupling to a primary winding of a first transformer;
a second terminal for coupling to a primary winding of a second transformer;
a third terminal for coupling to a ground reference;
a fourth terminal for coupling to a source of operating power;
a first power switch having an input coupled to the first terminal, an output coupled to the third terminal, and an activation gate;
a second power switch having an input coupled to the second terminal, an output coupled to the third terminal, and an activation gate;
a first control circuitry coupled to the first power switch activation gate and responsive to an error signal for driving the first power switch, the error signal derived from an internally generated compensation signal; and
a second control circuitry coupled to the second power switch activation gate and responsive to an error signal for driving the second power switch, the error signal derived from an internally generated compensation signal, wherein the second control circuitry is operated independent from the first control circuitry.
8. The power supply package of claim 7 , wherein the control circuitry coupled to the first power switch and the second power switch are based on a flyback topology.
9. The power supply package of claim 7 , wherein the power supply package is included in the case of a television monitor.