wiki:2012-05-09-LaserPowerMeeting

5/9/12 meeting to discuss power supplies in Laser box.

Conclusions

After discussion, we agreed on the following power supply configuration:

*Module* *V range* 'Operating V Imax (A) Power (W) *Load* *Notes*
Xg1 1.5-3.6 -3V 1?
Xg2 3.2-6 +3.3V 40 200 TECs normally on
Xg4 (2 par) 12-30 +28V 10 240 WLS normally off, controlled by Sys. Ctrl 2?
Xg7 5-28 -5V 5 120 -5V analog normally on
Xg3 6-15 +12V 20 240 Fans and +5V normally on

Notes:

Other action items:

will come on with the AC power. Eric will give Matt instructions on how to do this by modifying the system controller design. This is probably as simple as wiring the "GLOBAL ENABLE" (pin 6 on the connector) to +5V_Bias (pin 2) but this should be checked in the documentation. Other connections from backplane J9 to the power supply mainframe should be left as-is.

Preliminary Material

Current power module configuration:

*Module* *V range* 'Imax (A) Power (W) *Load* *Notes*
Xg1 1.5-3.6 50 125 Lasers normally off, controlled by Sys. Ctrl
Xg2 3.2-6 40 200 TECs normally on, not controlled/monitored?
Xg4 (2 par) 12-30 10 240 WLS normally on, not controlled/monitored?
Xg7 5-28 5 120 "fans" Also supplies all +5V power through regulators on Sys Ctrl
Xg3 6-15 (can't supply -5V!) 20 240 "electronics" Only very low current -5V analog power.

The power supply chassis provides low-current (250mA max) +5V called "+5V Bias". Currently this is used for all logic power on the system controller. The current is insufficient.

Our task for today is to re-think the scheme for electronics power and figure out which modules should come on with the AC power and which should be controlled by the system controller.

Here is one possible alternative configuration:

*Module* *V range* 'Imax (A) Power (W) *Load* *Notes*
Xg1 1.5-3.6 50 125 Lasers normally off, controlled by Sys. Ctrl
Xg2 3.2-6 40 200 TECs normally off, controlled by Sys. Ctrl
Xg4 (2 par) 12-30 10 240 WLS normally off, controlled by Sys. Ctrl
Xg7 5-28 5 120 -5V analog normally on
Xg3 6-15 20 240 Fans and +5V normally on

This can use the same complement of power supplies. It requires some small changes to the system controller board to derive all the +5V logic power from +12V.

Also, I would recommend that the Laser, TEC and WLS modules all be controlled by the system controller and at least their "power good" status monitored. There are two monitor/control ports wired through the backplane. This would require adding a third one.

Reference materials

Last modified 9 years ago Last modified on Nov 8, 2013, 10:17:53 AM