AA1700 Agamem Microelectronic, AA1700 Datasheet - Page 5

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

PRELIMINARY
■
1. Soft Start
A soft start function, which gradually increases the width of the output pulses at power on, will be applied if a
capacitor is connected to the SP pin. This can prevent rush currents and overshoot when the power supply is
turned on.
Soft start time can be measured by the following equation. (The time until the output ON duty reaches
approximately 50%)
2. Timer Latch Short Circuit Protection
When the load conditions suddenly change due to load effect, the short-circuit protection comparator outputs the
high-level signal (V
capacitor C
level, and the dead-time is set to 100%. However, the latch circuit is not reset unless the power for the latch
circuit is turned off or restarted by the on/off control.
©Copyright Agamem Microelectronics Inc.
Output section
Output current
setting section/
Control section
Entire device
HOW TO SET THE TIME CONSTANT FOR SOFT START AND SHORT CIRCUIT DETECTION
• Short circuit detection time
t
t
S
PE
[s] = 0.35 × C
[s] = 0.8 × C
PE
has been charged to approximately 0.8V, the latch circuit is set, the output terminal is fixed to low
Parameter
OM
Output voltage
Output source
current
Output sink current
Pull down resistance
Pin voltage
Input off condition
Input on condition
Pin current range
Stand-by current
Average supply
current
PE
+
PE
) and the capacitor C
[uF]
Agamem Microelectronics Inc.
[uF]
Symbol
PE
V
V
V
V
V
I
I
I
I
I
R
I
I
CCS
connected to the SP terminal starts charging. When the external
OFF
CTL
O –
OH1
OH2
ON
CC
OL1
OL2
O+
CTL
O
(Continued)
R
R
I
R
R
I
R
R
R
CTL pin open or V
R
O
O
5
B
B
B
B
B
B
B
B
= –10 mA
= 10 mA
= 390 Ω , I
= 750 Ω , V
= 390 Ω , I
= 750 Ω , V
= 390 Ω , V
= 390 Ω , V
= 390 Ω
= 390 Ω
Condition
—
—
O
O
CC
CC
O
O
= –15 mA
= 15 mA
AA1700
Constant Current White LED driver
= 0.9 V
= 0.3 V
= 1.8 V
= 1.8 V
CC
www.agamem.com.tw
–1.8
Min
–20
1.0
0.8
0.2
30
20
—
—
—
—
—
—
Value
Typ
–30
1.2
1.0
0.1
0.1
0.3
5.5
60
30
—
—
—
—
Max
–0.1
–20
–45
0.2
0.2
0.4
9.3
40
—
—
—
0
1
2007/1/22
Unit
µ A
µ A
µ A
mA
mA
mA
mA
kΩ
V
V
V
V
V