SS6652 Datasheet, PDF (1/6 Pages) Silicon Standard Corp. – Micro-Power Inverting DC/DC Controller

SS6652
n ^FEATURES
Micro-Power Inverting DC/DC Controller
n ^DESCRIPTION
l 2.4V to 7V input voltage operation.
l Adjustable output voltage up to -40V.
l Low quiescent current at 80µA.
l Pulse frequency modulation maintains high
efficiency (87%).
l 70KHz to 160KHz switching frequency.
l Power-saving shutdown mode (0.7µA typical).
l High efficiency with low cost external P-
channel MOSFET or PNP bipolar transistor.
n ^APPLICATIONS
l Negative LCD Contrast Bias for
1. Notebook & Palmtop Computers.
2. Pen-Based Data System.
3. Portable Data Collection Terminals.
4. Personal Digital Assistants.
l Negative Voltage Supply.
The SS6652 is a high-performance inverting
DC/DC controller, designed to drive an external
power switch to generate programmable negative
voltages, and is particularly suited to LCD bias
contrast applications. Efficiency of 87% can be
achieved with low cost PNP bipolar transistor
drivers. Output voltage can be scaled to -40V or
greater by two external resistors. A pulse fre-
quency modulation scheme is employed to main-
tain high-efficiency conversion over a wide input
voltage range. Quiescent current is about 80µA
and can be reduced to 0.7µA in shutdown mode.
With switching frequencies in the 70KHz to
160KHz range, the small size switching compo-
nents are ideal for battery powered portable
equipment, like notebook and palmtop computers.
n ^{TYPICAL APPLICATION CIRCUIT}
V_IN
2.4V ~ 7V
100µF ₊
C1
0.047µF
C4
VIN
VREF
SHDN
FB
CL
DHI
DLOW
GND
SS6652
R_CL
RB
470~1.8K
150µH
*L
Q1
9012
D1 1N5819
C2
100µF
+
R2
100K
R1
1M
C3
10nF
* Sumida CD-54 Series
V_OUT = -1.22V x R1/R2
Negative LCD Contrast Bias Power Supply
V_OUT
-12V~ -40V
-10mA
Rev.2.01 6/26/2003
www.SiliconStandard.com
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