AIC1650 AIC [Analog Intergrations Corporation], AIC1650 Datasheet - Page 4

• Manufacturer Part Number: AIC1650
• Description: 3-Cell, High-Efficiency, Inverting DC/DC Converter
• Manufacturer: AIC [Analog Intergrations Corporation]

PIN 1: VIN
PIN 2: VREF - 1.22V reference output. Bypass
PIN 3: SHDN- Logic input to shutdown the chip.
PIN 4: FB
PIN 5: GND - Power ground.
PIN DESCRIPTIONS
APPLICATION INFORMATIONS
1.8
1.6
1.4
1.2
0.8
0.6
0.4
0.2
1
0
4
Typical Application Circuit
6
- 4V to 20V input supply voltage.
- Feedback signal input to sense
with a 0.047 µ F capacitor to GND.
Sourcing capability is guaran-
teed to be greater than 250 µ A.
>1.5V = normal operation,
GND = shutdown
In shutdown mode DLOW and
DHI pins are at high level.
ground. Connecting a resistor
R1 to V
V
age:
V
8
REF
OUT
Max. Output Power vs V
= -(R1/R2 ) x V
pin yields the output volt-
10
OUT
V
12
IN
and a resistor R2 to
(V)
330µH
14
REF
IN
100µH
Inductor Value
16
120µH
150µH
18
180µH
220µH
270µH
300µH
20
The typical application circuit generates an adjustable
negative voltage for contrast bias of LCD displays.
Efficiency and output power can be optimized by us-
ing appropriate inductor and switch. The following
formulas provide a guideline for determining the op-
timal component values:
L
PNP :
RB
where, units: V
PIN 6: DLOW - Driver sinking output. Connected
PIN 7: DHI
PIN 8: CL
= (11.1 0.15
≅ 3 x L x (V
and
V
I
V
C,MAX
CEO
CE
β =
RB in Ω
−
IN
<
>
10
& V
0. 4V at I
IN
- Driver sourcing output. Connect
- Current-limit
≥
V
to DHI when using an external
P-channel MOSFET. When us-
ing an external PNP bipolar
transistor, connect a resistor RB
from this pin to DHI. RB value
depends on V
PNP bipolar transistor. By ad-
justing the RB value, efficiency
can be optimized.
to gate of the external P-channel
MOSFET or base of the PNP bi-
polar transistor.
clamps the switch peak current
to prevent over-current damage
to the external switch.
- 0.8)
200
IN
OUT
×
V )
+
IN
in V, I
×
V
×
OUT
I
C
V
OUT
OUT
= 200
I
IN
OUT
in A, L in µH,
input.
IN
V
AIC1650
×
, inductor and
×
IN
I
OUT
V
V
IN
OUT
This
4
pin