BaBar EMC Power Supply Requirements
Version of 04-Feb-97
Description
The power supply system is composed of 110 modules of the following specification:
- Voltage outputs: +10V, +5V, -5V
- Tolerance: +/- 1%
- Current per output: 9A
- Noise/Ripple: < 10mVp-p
If the vendor wishes, it may be possible to have two such modules per physical card. This must be discussed with the customer first.
All three output rails are floating with respect to each other and to earth.
All of these supplies will have remote sensing. They will be connected to the load via up to 30m of 2mm^2 (14 AWG) cable. The voltage drop down this cable at these currents could be 3V in each direction. The voltages are those required at the load.
In the following a "supply" is the single unit that supplies +10V, +/-5V to an IOB and a "regulator" is a device that supplies one of these voltages.
Physical Package
The following is a suggestion, alternatives should be discussed with the customer.
Probably a fully shielded 6U height module (depth negotiable). Ideally it would be the width of two VME modules so we can fit 10 units in a standard crate with one slot spare for monitoring. Other modularity is possible, after discussion with the
customer.
The vendor should supply crates for the modules, if needed they must include a fan tray. The output connector is negotiable, but could be a 15 pin DIN41612 H-type. Mains will probably come in on one of these also.
Front-Panel Controls
The module should have a front-panel on-off switch and an LED indicating if the supply is on.
If the module trips off, LEDs on the front-panel should allow the determination of why. For example there could be an 'over temperature' LED and LEDs to indicate which of the regulators caused the supply to shut down because of over current etc.
Remote Monitoring
We need to be able to read the voltage and current drawn from each regulator remotely. We will not want to set the voltage or current limits remotely. It is likely the monitoring will be performed using CAN bus.
Unless there is a low cost or otherwise preferable ready-made solution from the vendor we will have a single customer supplied monitoring board in each power supply crate, connected to the 10 supplies. There is then only one CAN link per crate. The
connection from supplies to monitoring board would then be differential sense lines via the backplane. The monitoring module would probably need to have its own power supply directly from the mains input.
Mains Power
The power supplies will be used in both the USA (in the system) and the UK (test rigs). There are several ways we can accommodate this:
- Have autoranging, universal input supplies that couldn't care less what the input voltage/frequency is. These may (or may not) be pricey.
- Have jumper selectable universal input supplies. The problem with this is that someone is bound to set the jumper to the wrong position at some point.
- Have USA only input and use transformers for units used in the UK.
Vendors should advise of the cost implications of these options.
Sequencing
All power supplies should ramp monotonically with the +10V output always greater than or equal to the +5V output.
Interlocks
Each regulator should shut off automatically in the case of over current, over voltage or over temperature condition at the power supply. Possibly "shut off" can mean "shut down" or "current limit". However, in order to protect the front-end electronics,
if any one regulator shuts off then all three in that supply should shut off together. This last requirement can be met by customer supplied electronics using the signals described below.
There should be a 'DC ok' output that indicates all outputs are on and within specification. This output should either be a relay (closed for off and open for on) or a voltage level, where on is between +3V and +30V and off is between -30V and +1V.
There should be a 'remote on/off' input that turns the output on and off. This input will be driven by an open-collector transistor. The power supply should be on when the transistor is not conducting and off when the transistor is conducting.
Safety
The power supplies must meet the following specifications:
- EN55022 Class B for EMI/RFI
- EN60950, LVD compliant
- The interconnection to and from the backplane must conform to IEE wiring regulations.
Deliverables
- Prototypes (delivery 4-6 weeks to UK)
- 3 x prototype power supply module
- 3 x crates (and backplanes) suitable for housing the modules
- Production (delivery approximately 9 months to UK or USA)
- 125 power supply modules enough crates (and backplanes) to house the 110 power supplies for the detector, plus five spares.
- Also interface specifications, MTBF analysis and user documentation for the above.
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