Pulse width modulator control circuit
Granted: September 3, 1991
Patent Number:
5045800
A circuit generates control signals used in pulse width modulation. A square wave signal generator generates a square wave signal based on the value of a sawtooth signal. The sawtooth signal has a maximum voltage level and a minimum voltage level. The voltage level of the sawtooth signal is compared with a first voltage slightly above the minimum voltage level. When voltage of the sawtooth signal is increasing and reaches the first voltage, a rising edge of the square wave is generated.…
Temperature-compensated integrated circuit for uniform current generation
Granted: August 6, 1991
Patent Number:
5038053
An integrated circuit has a first resistor and a second resistor. A base-emitter voltage differential is maintained across the first resistor to develop a first resistor current and a base-emitter voltage is maintained across the second resistor to develop a second resistor current. The first resistor current is mirrored and the second resistor current is subtracted from the mirrored current to obtain a reference current. The resistors have resistance values so that the products of each…
Self powering technique for integrated switched mode power supply
Granted: May 7, 1991
Patent Number:
5014178
A regulator circuit is connected to a transformer. The transformer has a primary winding connected to a rectified D.C. voltage signal and has a feedback winding. A feedback capacitor is coupled across the feedback winding of the capacitor. The regulator circuit includes a high voltage switching transistor, a pulse width modulator which controls the high voltage switching transistor and a high voltage power up transistor. At power up, the high voltage power up transistor connects the…
Regulated flyback converter with spike suppressing coupled inductors
Granted: April 16, 1991
Patent Number:
5008794
Flyback converters can generate multiple voltage levels by rectifying and filtering multiple windings on a single power transformer. Different voltages should be related by the turns ratio of the respective windings. Transformer leakage inductance causes leading edge voltage spikes on some windings causing the filters to peak charge to a higher value than expected. The addition of a small coupled inductor between two or more windings will block the leading edge spike allowing the filter…
High voltage MOS transistors
Granted: March 7, 1989
Patent Number:
4811075
An insulated-gate, field-effect transistor and a double-sided, junction-gate field-effect transistor are connected in series on the same chip to form a high-voltage MOS transistor. An extended drain region is formed on top of a substrate of opposite conductivity-type material. A top layer of material having a conductivity-type opposite that of the extended drain and similar to that of the substrate is provided by ion-implantation through the same mask window as the extended drain region.…
