Pico Systems

ASIC Motherboard Power Supply

This is a power supply designed to power one ASIC motherboard. It provides 6 to 7.5 V output from the supply, but regulates the actual voltage at the motherboard so it can compensate for IR drop in the supply cable. It can provide up to 6.67 Amos of the nominal 6 V power. It also supplies up to 300 mA of -6 V and 50 mA of +12 V as needed by the motherboard. It fits in a double-wide NIM slot, and uses only 120 V AC power. The unit requires a fan cooling rack if loaded above 2 Amps.

There is a digital Volt/Ampmeter on the front panel to read +6 V Voltage at the motherboard, and current as well as the source output Voltage so the effect of cable IR drop can be checked. -6 V Voltage can also be checked. A knob sets the output voltage and another sets the current limit. A meter switch position allows the current limit setting to be checked. If the + 6 V current exceeds the limit setting, the power supply will switch off, and the red LED will light. Flipping the switch to off and back on will reset the power supply.

Front Panel Connector:

Power Output - 37-Pin Female "D" Connector

Pin #	Signal
1	+ 6 V
2	Power Ground
3	Power Ground
4	- Sense
5	+ 12 V
6	Bias Ground
7	Bias 15
8	Bias 13
9	Bias 12
10	Bias 10
11	Bias Ground
12	Bias 7
13	Bias 5
14	Bias 4
15	Bias 2
16	Bias Ground
17	N.C.
18	N.C.
19	Temp Sensor -
20	+ 6 V
21	- 6 V
22	+ Sense
23	Power Ground
24	N.C.
25	Bias 16
26	Bias 14
27	Bias Ground
28	Bias 11
29	Bias 9
30	Bias 8
31	Bias 6
32	Bias Ground
33	Bias 3
34	Bias 1
35	N.C.
36	N.C.
37	Temp Sensor +

+6 V and Power Ground have multiple pins to share current. A twisted-pair cable should be used to bring the +6 V and Power Ground signals back from the motherboard connector to the + Sense and - Sense terminals of the power supply.

An internal patch board is provided inside the module to allow detector bias to be connected through the power cable to the motherboard.

An Analog Devices AD590JH Temperature sensor can be installed at a convenient place on the motherboard and read out at the power supply.

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