HT7660 Datasheet, PDF (1/9 Pages) Holtek Semiconductor Inc – CMOS Switched-Capacitor Voltage Converter

HT7660
CMOS Switched-Capacitor Voltage Converter
Features
· Simple conversion of V_DD to -V_DD
· Cascade connection (two devices are
connected, V_OUT= -2 V_DD)
· Boost pin for higher switching frequency
· Easy to use
- _{Requires only two external capacitors}
Applications
· RS-232 power supply
· On board negative supply for dynamic
RAMS
· Supply voltage splitter, V_O= ± V_DD/2
General Description
HT7660 is a monolithic CMOS switched-capaci-
tor voltage converter. HT7660 is designed to
complete a voltage conversion from positive to
negative. The only required external compo-
nents are two low cost electrolytic capacitors.
HT7660 includes a voltage regulator, an RC os-
cillator and four output power MOS switches.
Block Diagram
· No external diode required
· Typically with no load voltage conversion,
99.9% efficiency
· Typical power efficiency is 98%
· Wide operating voltage range: 3V to 12V
· Operation amplifier supply
· Data acquisition systems
· Positive voltage doubler
The frequency of an RC oscillator can be low-
ered by adding an external capacitor between
V_DD and the OSC pin, or an external clock can
be connected to the OSC pin to replace the origi-
nal oscillator. The LV terminal may be tied to
VSS to disable the voltage regulator. By doing
this, low voltage operation can be improved.
OSC
BOOST
RC
Oscillator
Voltage
Level Shifter
LV
Voltage
Regulator
VSS
1
VDD
CAP+
CAP
VOUT
Logic
Network
November 30, 1999