Download

PDF Abstract Text:

6W Inverter for MOS Logic supplies

ZTX650 7T 0.15 F 2T 5T

Design Note 28 Issue 2 January 1996
6W Inverter for MOS Logic supplies
The 6W inverter shown in Figure 1 has been designed to generate the extra power supplies required by popular MOS memories from a normal 5V TTL supply source. It may be used to supply up to eight 2808 read only memories which require supplies of +5V, -5V and +12V, or if the output components of the 12V section are reversed, the circuit will power over ten 5204 ROMs which require +5V and -12V supplies.
The inverter is a simple push-pull circuit which takes advantage of the high curre nt handling capability of the ZTX650 range. It oscillates at a frequency of approximately 25kHz to allow it to use a very small transformer (RM6), and also to render the inverter inaudible. The output characteristics are given in Figures 2 and 3. Output ripple is approximately 150mV peak to peak on both outputs.
ZTX650 7T 0.15 F 2T 5T
BY206 68 F 16V 1K
BY206 6T 200 33 6T 2T ZTX650 TFR1 100 F 10V 0V +5V 5T 7T BY206 BY206
0V + 100 F 10V 680
-5V Transformer details: FX3437 cores wound with: 2-0-2t, 29swg. 5-0-5t, 26swg. Bifilar 13-6-0-6-13t, 29swg.
REVERSE POLARITY IF -12V SUPPLY IS REQUIRED
Figure 1 6W Inverter Schematic.
DN28- 1
Design Note 28 Issue 2 January 1996
Figure 2 Output characteristics of +12V Supply against Load Current.
Figure 3 Output characteristics of -5V Supply against Load Current.
Table 1. Output Voltage of +12V Supply against Load Current.
Output Current 10 100 200 300 400 500 600
Output voltage 12.2 11.8 11.6 11.4 11.2 10.8 10.6 10mA load on -5V supply.
Output voltage 12.1 11.6 11.4 11.2 11.0 10.7 250mA load on -5V supply.