Pin driver for in-circuit test apparatus

Details Pin driver for in-circuit test apparatus Pin driver for in-circuit test apparatus

1991-02-01

1992-09-08

Karlsen, Ernest F.

Electricity: measuring and testing

Measuring, testing, or sensing electricity, per se

With rotor

324 731, 330263, G01R 3128, H03F 326

Patent

active

051461595

ABSTRACT:
A tri-state pin driver is formed in part, along with a pin sensor, on an integrated circuit. A pin driver and sensor are coupled to a common pin of a device under test. In normal mode, the pin driver drives a test signal. In high impedance mode, the pin driver is at a high impedance, enabling a sensor to monitor a response signal. The pin driver includes a driver stage formed off-chip by a pair of power transistors operated in the active region. The large power transistors enable a large current (i.e., +/-500 mA) to be sourced or sunk so as to drive a device under test and back-drive preceding circuits. Operating in the active region enables faster logic state transition times, and thus, a fast test rate, while reducing undesirable signal distortion. A predriver stage is configured as a unity-gain emitter follower. The predriver stage includes first and second signal paths. Each signal path includes a pair of transistors configured, during normal mode, as a transmission gate. When the pin driver output is high impedance, the transistor pairs instead form open circuits in which respective collector-emitter junctions provide breakdown voltage protection. The pin driver also includes a waveform generator which receives a test state signal for defining the pin driver output logic level, and an analog slew rate control signal for defining the pin driver slew rate. Off-chip diodes are used to set the output levels of the waveform generator and to provide reverse breakdown voltage protection at the high reference voltage and low reference voltage terminals.

REFERENCES:
patent: 3976940 (1976-08-01), Chau et al.
patent: 4176323 (1979-11-01), Odell
patent: 4490673 (1984-12-01), Blum et al.
patent: 4572971 (1986-02-01), Necoechea
patent: 4743841 (1988-05-01), Takeuchi
patent: 4818893 (1989-04-01), Domnitz
patent: 4864249 (1989-09-01), Reiffin
patent: 4866398 (1989-09-01), Gulczynski

Affiliated with

Also associated with

Rating

Pin driver for in-circuit test apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Pin driver for in-circuit test apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pin driver for in-circuit test apparatus will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-136491