Power supply controller having low startup current
US5471130A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 12, 1993 |
| Grant date | Nov 28, 1995 |
| Priority date | — |
| Expiry date | Nov 12, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05F1/56
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A power supply controller includes a comparator for providing a regulated voltage when an input voltage exceeds a reference voltage, so that a reference voltage is provided to drive a load discharge circuit. When the input voltage is less than the reference voltage, such as during a startup or sleep mode of operation of the controller, the load discharge circuit is driven by an output pulldown circuit so as to maintain minimum functions within the integrated circuit of the controller including turnoff of an external MOSFET. The output pulldown circuit senses the resulting absence of the regulated voltage using a first transistor coupled to be biased into nonconduction when the regulated voltage is not provided. This biases a second transistor into conduction to maintain a transistor within the load discharge circuit conductive. In this manner, the output powers its own operation, including the pulldown thereof. The controller enables a relatively small startup current to be used, utilizes multiple outputs, and eliminates temperature dependence of the startup current.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.