tc7660h Microchip Technology Inc., tc7660h Datasheet - Page 6

• Manufacturer Part Number: tc7660h
• Description: High Frequency 7660 Dc-to-dc Voltage Converte
• Manufacturer: Microchip Technology Inc.

TC7660H-2 10/1/96
TC7660H
Efficient Positive Voltage Multiplication/
Conversion
eration are bidirectional, the charge transfer can be per-
formed backwards as easily as forwards. Figure 9 shows a
TC7660H transforming –5V to +5V (or +5V to +10V, etc.).
The only problem here is that the internal clock and switch-
drive section will not operate until some positive voltage has
been generated. An initial inefficient pump, as shown in
Figure 9, could be used to start this circuit up, after which it
will bypass the diode and resistor shown dotted in
Figure 9.
TYPICAL PERFORMANCE CHARACTERISTICS
Since the switches that allow the charge pumping op-
Output Source Resistance vs. Supply Voltage
100
10k
10
–10
1k
–1
–2
–3
–4
–5
–6
–7
–8
–9
0
0
0
Output Voltage vs. Output Current
10 20 30 40 50 60 70 80 90 100
1
SUPPLY VOLTAGE (V)
OUTPUT CURRENT (mA)
2
C
3
I
C
2
4
=1
5
F
T A = +25 C
T A = +25 C
LV OPEN
6
7
8
6
(Circuit of Figure 1)
1.0 F
Output Source Resistance vs. Temperature
C 1
HIGH FREQUENCY 7660 DC-TO-DC
500
450
400
200
150
100
50
–1
–2
–3
–4
–5
0
5
4
3
2
1
0
–55
0
+
I OUT = 1 mA
Output Voltage vs. Load Current
T A = +25 C
V + = +5V
V + = +5V
V + = +2V
Figure 9. Positive Voltage Conversion
–25
10
1
2
3
4
20
TC7660H
0
TEMPERATURE ( C)
LOAD CURRENT (mA)
30
VOLTAGE CONVERTER
+25
SLOPE 55
40
+50
8
7
6
5
© 2001 Microchip Technology Inc.
50
V OUT = –V –
+75 +100 +125
1 M
60
V – INPUT
70
80
+
DS21466A
1.0 F