AA1700 Agamem Microelectronic, AA1700 Datasheet - Page 8

• Manufacturer Part Number: AA1700
• Description: Constant Current White LED Driver
• Manufacturer: Agamem Microelectronic

PRELIMINARY
©Copyright Agamem Microelectronics Inc.
C1815
Note:
1.Light striking the surface of the Cds causes a decrease in resistance, while darkness
produces a higher resistance. When the light is bright, Q3 is on and Q2 is off, AA1700
will enter stand-by mode and there is no output current provided. When the light is dark,
Q3 is off and Q2 is on, AA1700 will output current and driver the IR LEDs. If the light Is
gray, the Q2 and Q3 will enter active mode, the impedance of Cds will decide the
collector current of Q3 and also Impact on the Internal impedance of Q2, so the driving
current can be controlled.
2.VR1 is for light sensitive control, the value will decide how darkness of the light source
the IR LEDs will brighten.
Q2
390Ω
Vcc
CTL
SP
IN
1
2
3
4
CDS Control for IR LED
Agamem Microelectronics Inc.
8
7
6
5
GND
ER
CLK
P0
C1815
Q3
8
300Ω
R7
VR1
50K
Vcc
AA1700
Constant Current White LED driver
10uF
C8
www.agamem.com.tw
D3
R2
4.7KΩ
R8
Sensitive Resistor
CdS Light
2007/1/22