TC7662B Просмотр технического описания (PDF) - Microchip Technology
Номер в каталоге
Компоненты Описание
производитель
TC7662B Datasheet PDF : 11 Pages
| |||
CHARGE PUMP DC-TO-DC
VOLTAGE CONVERTER
TC7662B
Regulated Negative Voltage Supply
In some cases, the output impedance of the TC7662B
can be a problem, particularly if the load current varies
substantially. The circuit of Figure 12 can be used to over-
come this by controlling the input voltage, via an ICL7611
low-power CMOS op amp, in such a way as to maintain a
nearly constant output voltage. Direct feedback is advisable,
since the TC7662B’s output does not respond instanta-
neously to change in input, but only after the switching delay.
The circuit shown supplies enough delay to accommodate
the TC7662B, while maintaining adequate feedback. An
increase in pump and storage capacitors is desirable, and
the values shown provide an output impedance of less than
5Ω to a load of 10mA.
+8V
56k
50k
100k
50k
+8V
–
+
+
100µF -
1
8
2
7
3 TC7662B 6
4
5
–
10µF
+
V+
VOUT
+5 LOGIC SUPPLY
TTL DATA
INPUT
+
1µF –
16
4
15
1
8
2
7
3 TC7662B 6
4
5
1µF
+
12 11
IH5142
13 14
+5V
-5V
1
3
RS232
DATA
OUTPUT
Figure 13. RS232 Levels from a Single 5V Supply
800k
250K
VOLTAGE
ADJUST
100µF
Figure 12. Regulating the Output Voltage
© 2001 Microchip Technology Inc. DS21469A
7
TC7662B-8 9/11/96
Share Link: 