4560/4570 RADF
18 - 56
Nov. 1997 © TOSHIBA
18.11.4
Rush current limitation circuit
This circuit is for suppressing rush current, that flows to current regeneration capacitor C23 included in
the driver motor drive circuit, to a fixed value. This circuit comprises a limiting resistor and FET Q5 that
causes current to flow at steady operation.
During the times that the ZD2 cathode reaches 16 V from when the ADF open/close switch, feed cover
switch and exit cover switch close, base current is not supplied to Q3 causing the circuit to become OFF,
and IC11 pin 5 becomes H-level. At this time, as base current is not supplied to Q2 and the circuit is OFF,
Q5 becomes OFF and the current flows through R37.
On the other hand, when the cathode of ZD2 exceeds 16 V, base current flows to Q3, and the circuit
becomes ON. After a delay according to the time constant of R2 and C35, IC11 pin 5 becomes L-level.
For this reason, base current is supplied to Q2, the circuit becomes ON and Q5 becomes ON. As a result,
the current that had been flowing to R37 up till now, flows through Q5, and the current limitation is
released.
R38 is a discharging resistor for immediately withdrawing the loaded accumulated to C23 when the ADF
open/close switch, feed cover switch and exit cover switch become open.
Содержание 4560
Страница 210: ...Nov 1997 TOSHIBA 13 43 4560 4570 ADU 13 8 7 Harness connection diagram ...
Страница 213: ...4560 4570 ADU 13 46 Nov 1997 TOSHIBA 13 8 9 PC board assembly ...
Страница 238: ...Nov 1997 TOSHIBA 14 25 4560 4570 CIRCUIT DIAGRAMS 14 5 Power Supply Circuit PS ACC A 115V ...
Страница 239: ...4560 4570 CIRCUIT DIAGRAMS 14 26 Nov 1997 TOSHIBA B 230V ...
Страница 243: ...Nov 1997 TOSHIBA 16 1 4560 4570 PC BOARD 16 PC BOARD ASSEMBLY 16 1 PWA LGC ...
Страница 244: ...4560 4570 PC BOARD 16 2 Nov 1997 TOSHIBA 16 2 PWA PNL ...
Страница 245: ...Nov 1997 TOSHIBA 16 3 4560 4570 PC BOARD 16 3 PWA KEY1 16 4 PWA KEY2 ...
Страница 246: ...4560 4570 PC BOARD 16 4 Nov 1997 TOSHIBA 16 5 PWA ERS ...
Страница 247: ...Nov 1997 TOSHIBA 16 5 4560 4570 PC BOARD 16 6 PS ACC A 115V ...
Страница 248: ...4560 4570 PC BOARD 16 6 Nov 1997 TOSHIBA B 230V ...
Страница 249: ...Nov 1997 TOSHIBA 16 7 4560 4570 PC BOARD 16 7 PS HVT ...
Страница 341: ...Nov 1997 TOSHIBA 18 83 4560 4570 RADF 18 16 Circuit Diagrams Wire Harness 18 16 1 General circuit diagram ...
Страница 342: ...4560 4570 RADF 18 84 Nov 1997 TOSHIBA 18 16 2 Control PC board circuit PWA F LGC 770 ...
Страница 343: ...Nov 1997 TOSHIBA 18 85 4560 4570 RADF 18 16 3 Harness connection ...