In a DC-DC converter of the quasi-resonant converter type, an inductive element (L'), which determines resonance, is provided as a part of the smoothing inductor (L) in the load circuit or as an additional inductive element which is magnetically coupled to the smoothing inductor (L). During energy transmission of the DC-DC converter, a part of the resonant current flows without delay to the output of the DC-DC converter, and into its capacitor (CG) on the output side. In consequence, the influence of the phase shift on the smoothing inductor is considerably reduced, as a result of which the dynamic characteristic of the DC-DC converter is improved.

DC-DC converter, in particular of the quasi-resonant type

The power supply converts alternating current voltage to a direct current voltage which is in turn converted to a pulse width modulated voltage. A circuit arrangement is provided responsive to the pulse width modulated voltage to produce N output direct current voltages each having a different predetermined value, where N is an integer greater than one. A feedback circuit is provided between the circuit arrangement and the circuit providing the pulse width modulated voltage to provide a substantially constant value for the N output voltages when a varying load is presented to the power supply. A current transformer arrangement is coupled in series in the feedback circuit to provide wide bandwidth and low droop without oscillation for the power supply when the power supply is subjected to a step load (a step from no-load up to full-load).

Regulated power supply for rapid no-load to full-load transitions

1. Method for the regulation and current limitation of a direct current ringing choke converter by means of a pulse-width-controlled electronic switch (6), which is periodically ignitable under external control and extinguishable in dependence on a comparator signal, wherein a reference voltage (Uref) and an evaluation signal are compared for the formation of the comparator signal and wherein the evaluation signal is formed from the sum of a signal for the output magnitude to be regulated and a signal which is supplied by a current converter (10) which transforms the total current through the electronic switch, characterised thereby, that a unidirectional voltage value, which is proportional to the peak value of the total current through the electronic switch (6) and which is obtained by peak integration of the current converter output signal, serves as signal for the output magnitude to be regulated.

Method for regulation and current limitation of a switched d.c. ringing-choke converter

In the case of a switched-mode regulator having current limiting, a current transformer (SW) is arranged in the load circuit. The secondary of this current transformer (SW) is connected to a diode bridge circuit (D1, D2, D3, D4) between whose output terminals the series circuit formed by a reference element (ZD1) and a current measuring resistor (R1) is connected. The voltage dropped on the current measuring resistor (R1) is fed to an error amplifier (FV) which controls the switched-mode regulator control element (T1). Electrical power is supplied to the error amplifier (FV) via the reference element (ZD1). As a result of this construction, the load current can be detected very accurately and without any delay (Figure 1).

Switched-mode regulator having a current limiting device

Schaltregler mit einrichtung zum erfassen des mittelwertes der ausgangsspannung

A voltage controller is operated by pulse width modulation and a current limiter is provided. A current transformer (W) has its primary winding (I) connected in series with the capacitor (K1) and a diode (D2) and with a capacitor (K2) is connected to the secondary winding (II) in parallel with a load resistor (B). It generates a DC voltage proportional to the output current (IA). The diode (D2) and transformer secondary winding (II) are so arranged that only capacitor (K1) discharge current is evaluated, with the diode (D2) and capacitor (K2) operating as a peak detector.

Klaus Link

Papers

DC inverter with capacitor and voltage controller - has current transformer connected to diode and capacitor for output current evaluation