Pad driver
US6342803B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Oct 30, 2000 |
| Grant date | Jan 29, 2002 |
| Priority date | — |
| Expiry date | Oct 30, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K19/00315
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
The present invention includes a pad driver circuit that has a driver, a power-on circuit coupled to the driver and a power-off circuit coupled to the driver. The power-on circuit is coupled to a pad via the power-off circuit. The power-on circuit provides a high impedance path between the pad and a power supply, particularly when the power supply is off. The power-off circuit provides a stepped-down voltage to the driver when the voltage signal is received. The driver is an open drain driver that includes series pull-down devices. The pad driver further includes a second power off circuit coupled to the driver. The power-on circuit provides a power supply voltage to the driver when a power supply is on. The power-on device preferably includes an inverter coupled to receive a power supply voltage and a clamp coupled to receive an output of the inverter wherein the clamp provides a voltage responsive to the power supply voltage. In operation, the present invention provides for a pad driver that is tolerant of voltages that are greater than a power supply voltage provided to the pad driver. To that end, the power-off circuit steps down a voltage received from the pad. This stepped do…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.