Below ground current sensing with current input to control threshold
US5245526A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 7, 1992 |
| Grant date | Sep 14, 1993 |
| Priority date | — |
| Expiry date | Feb 7, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M1/0009
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An embodiment of the present invention is a switching power supply with high voltage positive and negative power inputs, a system ground, a sensing resistor placed between the negative power input and system ground, first and second load outputs with the first load output connected to the positive power input, and a comparator having first and second comparison inputs and a comparison output with the second comparison input connected to the system ground. A constant-current source is connected to the first comparison input of the comparator. A power MOSFET switch transistor has its drain connected to the second load output, its source connected to the system ground, and its gate controlled by the comparison output of the comparator. And a control resistor is connected between the second power input and said first comparison input of the comparator. The constant-current source, control resistor, and sensing resistor are such that when a predetermined current flowing through the first and second load outputs reaches a predetermined level (the current limit), the voltage developed across the sensing resistor will be equal to the voltage dropped across the control resistor, and the com…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.