MAX1605 Datasheet, PDF (9/12 Pages) Maxim Integrated Products – 30V Internal Switch LCD Bias Supply

30V Internal Switch LCD Bias Supply
V_IN =
0.8V TO
V_OUT
L1
10µH
C5
1µF
R3
C3
1Ω 0.1µF
D1*
V_NEG
-19V
D2*
C2
1µF
V_CC =
2.4V TO
5.5V
C6
0.1µF
ON
OFF
V_CC
LX
MAX1605
D3**
R1
240kΩ
C1
1000pF
C4
0.01µF
LIM
FB
SHDN
GND
R2
16.5kΩ
*D1, D2 = CENTRAL SEMICONDUCTOR
CMPD7000 DUAL
**D3 = CENTRAL SEMICONDUCTOR
CMSD4448 (1N4148)
Figure 4. Negative Voltage for LCD Bias
saturation region. When shut down, the input voltage
exceeds the emitter voltage so the inactive transistor
provides high-impedance isolation between the input
and output. Efficiency will be slightly degraded due to
the PNP transistor saturation voltage and base current.
Chip Information
TRANSISTOR COUNT: 2329
V_IN = 0.8V TO V_OUT
L1
10µH
R3 = 180kΩ
V_CC = 2.4V TO 5.5V
V_CC
LX
MAX1605
LIM
FB
ON
SHDN
GND
OFF
V_SET = 18.3V
(V_OUT + 0.3V)
V_OUT = 18V
2N2907A
R1
R2
Figure 5. Output Disconnected in Shutdown
_______________________________________________________________________________________ 9