Power Supplies - Overview, Fundamentals, Hints and tricks

Power Supply Operation principles

Switched mode

- high efficency
- compact dimensions also for high output power
- good price-to-output power relationship
- but:
– more ripple/noise, lower accuracity (not for RF use !)
– slower output regulation and programming (restricted use at puls loads, poor throughput at production test systems)

Linear regulated (Dropper)

- low ripple/noise, high accuracity
- fast in programming and regulation (puls loads !)
- but:
– more expansive in weight, dimensions, prices
– lower efficiency

Operation functions
– Remote Sensing
– Parallel and seriel operation ability
– Master/Slave operation
– Arbitrary function
– Remote controll
– analog
– IEEE488
– RS232
– LAN
– other
– Readback of actual values (V, C)
– Storage of test setups
– Storage of measured values
– Trend indications
– Sink capability

Protection functions
– OVP (Overvoltage protection)
– OCP (Overcurrent protection)
– FB (Foldback)
– OTP (Overtemperature protection)
– ON/OFF key
– DFI/RI (Discrete fault indicator / Remote inhibit)
– Softlimits

Some background about Batteries

Methods for Battery impedance determination:

1. 1kHz AC measurement ; result: RAC
- % expensive
- % interpretation is difficult, because mainly valid for a single cell and one electrode only (and not for battery packs )
- % discharging process is different to the behavior of the real DUT (measurement at t=0)
2. Current transients measurement; result: RDC
- % lower costs
- % result includes also the capacitive components of the whole battery pack, therefore the real 3. Device Under Test behaviour can be simulated
- % more valid information about aging status of the battery pack