Datasheet

 2002-2012 Microchip Technology Inc. DS21457D-page 13
TC7116/A/TC7117/A
5.0 TC7117/TC7117A POWER
SUPPLIES
The TC7117/TC7117A are designed to operate from
±5V supplies. However, if a negative supply is not avail-
able, it can be generated with a TC7660 DC-to-DC con-
verter and two capacitors. Figure 5-1 shows this
application.
In selected applications, a negative supply is not
required. The conditions for using a single +5V supply
are:
1. The input signal can be referenced to the center
of the Common mode range of the converter.
2. The signal is less than ±1.5V.
3. An external reference is used.
FIGURE 5-1: Negative Power Supply
Generation with TC7660
V
REF
+
V+
TC7117
TC7117A
36
10μF
V
IN
+
V
IN
-
COM
GND
32
31
30
21
10μF
V
IN
V-
(-5V)5
3
8
2
4
+5V
35
TC7660
26
+
+
+
–
LED
Drive