MCE Power

Power Requirements

There are two types of MCE subracks:

• MCE72: contains up-to 10 cards and can read up to 32 columns. In the past, this also contained a power supply unit (PSU)
• MCE48: contains up-to 7 cards and can read up to 16 columns.

The power requirements of a few typical subrack configurations are given below. To compute power and current requirements for a particular configuration, use: http://e-mode.phas.ubc.ca/mce/cgi-bin/power.cgi .

Configuration		MCE48 RC_RevE BC_RevF1	MCE48 RC_RevB BC_RevF0	MCE72 RC_RevE BC_RevF0	MCE72 RC_RevE BC_RevD	MCE72 RC_RevB BC_RevD
Voltage
Vcore1	3.0V	3.2A	2.7A	5.4A	5.3A	4.3A
Vlvd	4.5V	2.9A	2.9A	3.26A	3.1A	3.1A
Va+	6.2V	3.5A	8.6A	6.4A	5.7A	14.5A
Va−	−6.2V	1.0A	1.3A	2.3A	1.8A	1.4A
Vah2	10.0V	—	0.01A	—	0.06A	0.09A
Total Power		50.1W	82.5W	85.0W	77.2W	125.7W

¹: Minimum V_core supply for older version of cards can be as low as 2.5V, but newer RC and BC require minimum 3V see note. The numbers in this table assume a V_core of 3V.
²: The 10V V_ah supply is only used when Readout Card Rev. B (or older) or Bias Card Rev. D (or older) are present in the subrack. V_ah was used to generate reference voltages for DACs.
³: When using mux11d squid chips, unused DACs on Address Card can be turned off and 1 Bias Card can be eliminated. This will amount to 10W of power savings.

For card specific power requirements, see MCE Card Specific Power Requirements

Connector & pinout

The MCE uses Winchester MRA-34P-G on the front panel.

	A +Vah +10V		B AGND
C −Va −6.2V		D AGND
	E +Va +6.2V		F AGND
H +Va +6.2V		J AGND
	K +Va +6.2V		L AGND
M +Va +6.2V		N DGND
	P +Vlvd +4.5V		R DGND
S +Vlvd +4.5V		T DGND
	U +Vlvd +4.5V		V DGND
W +Vcore +3.0V		X DGND
	Y +Vcore +3.0V		Z DGND
a +Vcore +3.0V		b DGND
	c CC_SREQ†		d PS_MOSI†
f Fan GND‡		g BRST†
	h CC_MISO†		i PS_SCLK†
j Fan +12V‡		k PS_CS†
	m SIG_RET†		n SIG_RET†

†: Only used by PSUC.
‡: Optional power lines for subrack top plate fans.

Full details can be found under Winchester connector, here: 48HP Front-Panel Power Connection

Note that the older 5-MDM SCUBA-2 style MCE had 2 Circular Amphenol connectors on the front panel of the linear feed card. Pinout is here: Amphenol pinout. The linear-feed card connects power from these circular connectors to the Winchester power connector on the back panel.

Powering up an MCE

There are different solutions for powering up an MCE.

Linear Supplies

A straight-forward method is to use linear supplies configured to satisfy the above requirements. In that case the MCE has to be equipped with the right Linear-Feed connector in the front.

The set of linear supplies listed below (or similar supplies) are suitable.

Option 1

+Vcore	IHC5-6/OVP (adjustable)	3V	5A
+Vlvd	IHB5-3/OVP	4.5V	3A
+Va	IHE5-18/OVP	6.2V	15A
−Va	IHB5-3/OVP	-6.2V	2A
+Vah1	IHA15-0.5	10V	0.1A

¹: +V_ah or 10V supply only used when Readout Card Rev. B or Bias Card Rev. D is present in a subrack.

• Open-Frame PSU Wiring, Bill-of-Materials, Assembly Instructions
• MCE-to-PS Cable Wiring , Bill-of-Material

Option 2

+Vcore	Kepco JQE 6-22M (adjustable)
+Vlvd	Power One HC5-6/OVP
+Va	Kepco JQE 15-25M (adjustable)
−Va	Kepco JQE 15-25M (adjustable)
+Vah1	Power One HAD15-0.4-A

¹: +V_ah or 10V supply only used when Readout Card Rev. B or Bias Card Rev. D is present in a subrack.

As a slightly out-of-date example, here is how we setup our linear supplies in the lab (for 1 MCE).

• Linear_PS Wiring Diagram

• Linear PS Assembly Instructions

Vicor Switching Supplies (24V-in)

See Vicor Power Supply

The MCE can alternatively be equipped with a 18–36Vin (24Vin nominal) switching supply designed for use in balloon-based experiments. We are currently debugging a prototype design based on Vicor supplies. A preliminary schematics can be found here

AC-powered Switching Supplies (obsolete)

A 3-MDM MCE48 powered by an external PSA attached to an ACDCU.

The MCE can be equipped with a switching supply (PSA) that is powered through a front-panel Amphenol connector that takes ±150V DC. The ±150V is generated by an external AC-DC unit (ACDCU) that can reside far from the MCE. The ACDCU is designed and supplied by UBC.

The PSA is equipped with a controller card that allows monitoring voltage/current levels of the MCE by issuing a command from the MCE control PC. See psc_status.

This solution is obsolete and no longer in production. Ground-based experiments should use linear supplies. For balloon-based experiments, use the 24-V Vicor supply.