JPS5937665B2 - switching regulator - Google Patents

Description

[Detailed Description of the Invention] This invention aims to shorten and reliably switch on/off times of transistors, reduce switching losses, and increase overall efficiency when controlling the current of an inductance load using a transistor switching regulator. This relates to switching regulators.

Figure 1 is a circuit diagram of a conventional switching regulator.
The voltage applied from the input power source 7.8 is applied to the load inductance 6 by the on/off action of the transistor 1.

The on/off control signal is applied to the pulse transformer 4,
A voltage is applied from the resistor 2 to the base and emitter poles of the transistor 1, turning the transistor 1 on and off. A resistor 3 is inserted between the base and emitter of the transistor 1 to prevent noise. However, in the conventional circuit, as the output increases, the power capacity of the transistor 1 also increases, and the switching time is longer as part of the operating characteristics, resulting in large switching losses and poor efficiency. The present invention was made in view of the above circumstances, and uses a current transformer with three windings to reduce the switching time of the transistor and enables a highly efficient switching regulator.

An embodiment of the present invention will be described below with reference to FIG. In FIG. 2, a current transformer 11 has three windings 12, 13.
, 14, and the black circle symbol in the figure indicates the polarity.

The winding 12 is placed between the transistor 1 and the inductance load 6, and the winding 13 is placed in series with the commutating diode 5. Winding 14 is connected to the base pole of transistor 1 through resistor 10 . Now, when transistor 1 is turned on, current will flow through transistor 1 and winding 12 of transformer 11. At this time, a current to cancel the ampere turn with the winding 11 flows through the winding 14 through the resistor 10, the base pole and the emitter pole of the transistor 1, so that the transistor 1 is easily turned on. Further, when the transistor 1 is turned off, the current flowing through the inductance load 6 is commutated to the commutating diode 5. At this time, the current flows through the winding 13 and the current that should cancel the ampere turn flows through the winding 14, the diode 9, and the resistor 10, so a voltage drop across the diode 9 is created between the emitter and base of the transistor 1. A reverse bias voltage corresponding to is applied to facilitate turning off the transistor 1. That is, the role of these transformers is to shorten the switching time of the transistor by using the positive feedback current, thereby reducing loss during switching and providing a highly efficient switching regulator.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a switching regulator using conventional transistors, and FIG. 2 is a circuit diagram of a switching regulator according to an embodiment of the present invention. In the figure, 1 is a transistor, 5 is a commutation diode, 6 is a load, 11 is a current transformer, and 12, 13, and 14 are windings.

Claims (1)

[Claims] 1. In a switching regulator that drives an inductance load having a commutating diode, a switching transistor connected in series to a line connecting a power supply and the inductance load, and a diode having an anode connected to the base and a cathode connected to the emitter of the switching transistor and a pulse transformer having a secondary winding connected in parallel to the diode through a first resistor, and three windings each insulated, the first winding being connected to the emitter of the switching transistor. a current transformer connected in series to a line connecting the inductance load, a second winding connected in series with the commutation diode, and a third winding connected in parallel with the diode through a second resistor; A switching regulator characterized by: