Abstract: A fast lossless power MOSFET gate capacitance (C) driver uses a 3-winding transformer (T) to secure clamping (N, Vc, D) of the turn-on voltage level by coupling of the winding (N1) in the capacitance charging circuit to that (N) across the clamping potential (Vc) in series with a clamping diode (D). A similarly coupled winding (N2) in the discharging circuit can ensure clamping of the turn-off level, both rise and fall starting at zero current and being sinusoidal. Alternatively, a high Q constant current charge can be used with the charging circuit switch (S1) DC isolated from the capacitance and using the magnetising current built up in the transformer. Instead of clamping the turn-off level, the discharging circuit can be switched (S2) during magnetising current build-up (S1) using a separate inductance to reverse the capacitance voltage in a half-wave resonant circuit.

Abstract: An full bridge Zero-Voltage-Switched DC/DC converter with the four MOSFET snitches feeding the primary winding (T1) of the output transformer (T1) through a series inductance (L) and a series DC blocking capacitance (C) uses two MOSFET asynchronous rectifiers ((Q2) in its full wave output section. Each ((Q2) is serially connected between the output transformer (T1) and the output shunt capacitance (C') through the primary winding (T21) of a transformer detecting its drain current. The secondary winding (T22) of the detector transformer is shunted by a pair of resistances (R1/R'1) each in series with the base-emitter junction of a bipolar transistor (Q1/Q'1), the two transistors of complementary polarity forming a totem-pole branched across an auxiliary winding (T12) of the output transformer. The totem-pole output coupled (R2) to the gate of the MOSFET (Q2) switches its state upon the drain current value crossing the adjustable (R1/R'1) low value of the detector transformer magnetising current.

Abstract: A power supply shunt regulator (PSSR) regulates the current flowing to a branch (FET, L.sub.D, CSR) coupled in parallel to a power supply (SA) and an electrical load (EL). The regulator limits the discharge current from a parasitic capacitance (PSC) of the power supply (SA) when a shunt switch (FET) included in the branch is turned "ON". An active negative feedback loop (CLM, FET) therefore regulates the current flow through the branch by measuring a voltage drop over a current sensing resistor (CSR) included in the branch and by deriving a control signal (ACTRL) for the shunt switch in such a way that this voltage drop is critically damped to a maximum voltage drop. This damping can be done in a simple way by selecting the shunt switch to be a field effect transistor. Due to the fact that an inductor (L.sub.H) is coupled to the source of the shunt switch, stable operation is insured.