Linda W Chu

US Patent:

8013632, Sep 6, 2011

Filed:

Dec 15, 2009

Appl. No.:

12/638799

Inventors:

Jack Chui - Fremont CA, US
Linda Chu - San Jose CA, US
Toan D. Do - San Jose CA, US

Assignee:

Altera Corporation - San Jose CA

International Classification:

H03K 19/0175

US Classification:

326 82, 326 81, 326 38

Abstract:

Integrated circuits such as programmable logic devices are provided with hotsocket detection circuitry. The hotsocket detection circuitry monitors signals on data pins and power supply voltages. If the data pins become active before the power supply voltages have reached appropriate levels, a hotsocket condition is identified. When a hotsocket condition is identified, driver circuitry on the integrated circuit can be disabled by a hotsocket signal. The integrated circuit may include multiple blocks of input-output circuitry, each of which includes a local hotsocket circuit that uses global hotsocket and power-on-reset signals in disabling input-output circuitry in that input-output block. A power supply circuit in each input-output block may ensure that the local hotsocket circuit in that input-output block is powered.