G.
Active Clamp
The purpose of Clamp circuitry (Figure S-5) is to pull down the output voltage while two
sets of Inverter MOSET are OFF. The Clamp circuitry is active during the period of zero Volt.
of square wave at battery mode.
The Q22 is activated while the CLAMP-OFF signal (from pin 27 of CPU) goes to HI .
If either one of the two MOSFET sets turn on (Q20/Q24 or Q023/Q25), the CLAMP-OFF
signals will remain HI.
When UPS at line mode, the CLAMP-OFF signal remains HI. This turns on U07 to turn
off Q22. At this time the Clamp circuitry is not active. When the CLAMP-OFF is LOW, U07
turns OFF and Q22 turns on. This pulls down output voltage to approximately zero at battery
mode. Figure W-8 illustrates the relationship of the output waveforms and the CLAMP-OFF
signal.
17
Summary of Contents for 400VA
Page 8: ...Figure S 1 Control Power circuit 6 ...
Page 9: ...CH1 C15 GND Figure W 1 Cold Start 7 ...
Page 11: ...Figure S 2 Charger circuit 9 ...
Page 13: ...Figure S 3 Line and Zero Crossing Detecting circuit 11 ...
Page 14: ...CH1 Line I P CH2 Q14 collector Figure W 2 Zero Crossing 12 ...
Page 16: ...Figure S 4 Inverter circuit 14 ...
Page 17: ...CH1 DS1 CH2 Output Voltage 1 200V Figure W 3 Inverter Circuit 1 15 ...
Page 18: ...CH1 DS2 CH2 Output Voltage 1 200 Figure W 4 Inverter Circuit 2 16 ...
Page 20: ...CH1 CLAMP OFF signal CH2 output voltage 1 200V Figure W 5 Clamp circuit 18 ...
Page 23: ...Figure S 5 CPU circuit 21 ...
Page 24: ...Figure S 6 Relay Circuit 22 ...
Page 25: ...CH1 C10 GND CH2 Output Voltage 1 200V Figure W 6 Relay speed up capacitor 23 ...
Page 27: ...Figure S 7 Panel circuit 25 ...
Page 33: ...Figure W 7 Battery mode examination flowchart Figure W 8 Line mode examination flowchart 30 ...