An article of manufacture comprising a flyback converter (e.g., 100), the flyback converter comprising:
- a primary side (e.g., 110) comprising an input port (e.g., 112);
- a secondary side (e.g., 130) comprising an output port (e.g., 136), wherein the secondary side is galvanically isolated from the primary side;
- and
- a power transformer (e.g., T1) configured to transfer input power received at the input port to provide output power at the output port, wherein:
- the primary side further comprises a primary-side switch (e.g., 116) configured to selectively enable the input power at the input port to be transferred via the power transformer to the output power at the output port;
- the secondary side further comprises a demand pulse generator (e.g., 144) that (i) determines when to turn on the primary-side switch based on output voltage or output current at the output port and (ii) generates corresponding demand pulses (e.g., DP);
- the primary side comprises a primary-side magnetically coupled conductor (e.g., 118);
- the secondary side comprises a secondary-side magnetically coupled conductor (e.g., 134) configured to be magnetically coupled to the primary-side magnetically coupled conductor to convey the demand pulses from the secondary side to the primary side;
- the primary-side switch is turned on in response to a demand pulse conveyed from the secondary side to the primary side;
- the demand pulse generator comprises:
- an n-type transistor (e.g., Q1) having a base, a collector, and an emitter and characterized by a turn-on threshold voltage;
- a p-type transistor (e.g., Q2) having a base, a collector, and an emitter and characterized by a turn-on threshold voltage, wherein the collector and emitter of the n-type transistor are connected in series with the collector and emitter of the p-type transistor such that, when the two transistors are turned on, current flows from the collector of the n-type transistor to the collector of the p-type transistor;
- and
- a positive-feedback capacitor (e.g., C1, C2) connected between the collector of a first (e.g., Q2, Q1) of the two transistors and the base of a second (e.g., Q1, Q2) of the two transistors, wherein:
- the demand pulse generator is configured such that (i) the two transistors turn on together when the voltage at the base of the n-type transistor exceeds the voltage at the base of the p-type transistor by at least the sum of the turn-on threshold voltages of the two transistors and (i) the two transistors turn off together when the voltage at the base of the n-type transistor fails to exceed the voltage at the base of the p-type transistor by at least the sum of the turn-on threshold voltages of the two transistors;
- and
- the positive-feedback capacitor ensures that the two transistors turn fully on and off together.