Browse Prior Art Database

Regulated Power Supply

IP.com Disclosure Number: IPCOM000091113D
Original Publication Date: 1969-Oct-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 4 page(s) / 82K

Publishing Venue

IBM

Related People

Malia, JF: AUTHOR

Abstract

Power supply 10 is a constant pulse width, variable frequency switching type regulator. Unregulated three-phase input voltage Vac is fed to terminals 11a...11c. Vac is rectified in identical parallel connected full-wave rectifiers FWR's 12A and 12B. The unregulated FWR DC outputs V1 are decoupled to chassis ground by identical capacitor arrangements 13A and 13B to mitigate RF interference. Each FWR output is terminated on one of input filter banks 14A and 14P. Each of these is connected to two power chains of four identical chains 1...4.

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Regulated Power Supply

Power supply 10 is a constant pulse width, variable frequency switching type regulator. Unregulated three-phase input voltage Vac is fed to terminals 11a...11c. Vac is rectified in identical parallel connected full-wave rectifiers FWR's 12A and 12B. The unregulated FWR DC outputs V1 are decoupled to chassis ground by identical capacitor arrangements 13A and 13B to mitigate RF interference. Each FWR output is terminated on one of input filter banks 14A and 14P. Each of these is connected to two power chains of four identical chains
1...4.

Energy supplied by chains 1...4 maintains the regulator output capacitor filter bank 15 charged to the required regulated output voltage V2. Capacitors 16A and 16B, associated with bank 15, decouple V2 to chassis ground to reduce RF interference. Output V2 of bank 15 connects to load 17.

Each power chain includes transistorized power series switch 18, or 19, flywheel diode 20 and capacitor 21. During power chain operation, switch 18 is alternately turned on for a fixed time period tk, e.g., 12 us, and then turned off for a period determined by V2 as sensed by controller 22. With transistor -8 on, current through inductor 19 increases linearly at a rate directly proportional to the magnitude of the voltage applied across inductor 19 by transistor 18. Inductor 19 thus stores energy at a rate depending on the difference between V1 of the FWR and, output V2. When transistor 18 is turned off, stored energy in inductor 19 continues to supply current to bank 15. However, this current is now routed through diode 20. The inductor current decreases linearly at a rate proportional to the magnitude of V2. Capacitor 21 allows a large percentage of the recovery turnoff current of diode 20 to be fed to the collector of transistor 18 through a low- inductance loop, thus reducing the diode recovery time and radiated noise.

For a given output load, V2 attempts to rise as V1 rises. Controller 22 responds by decreasing the frequency with which transistor 18 is turned on. As a result, the input power to the regulator is approximately constant given load 17 and independent of Vac. With a fixed V1, controller 22 responds to an increasing output load, i.e., decreasing V2, by increasing the frequency with which transistor 18 is turned on.

The base current drive for each switches, e.g., transistor 18 of chains 1...4, is provided by the coaction of the transformer coupling circuits 23A...23D and their associated current source circuits 24A...24D respectively.

With both inputs at up levels to each Dot-Nand gate 25...28, their commonly connected outputs are effectively connected to ground. As a result, transistorized current source 29, via resistor 29', furnishes the drive current for its transformer 30. Transformer ringing is damped by resistor 31. When transistor 29 is turned off, by either of the inputs to gates 25...28 at a down level, transformer recovery occurs. During recovery, the transformer ma...