APE1630 Advanced Power Electronics Corp., APE1630 Datasheet - Page 5

• Manufacturer Part Number: APE1630
• Manufacturer: Advanced Power Electronics Corp.

Specifications of APE1630

• Support Voltage (min.): 8V
• Support Voltage (max.): 32V
• Frequency: 1MHz
• Output Current: 1A
• Package: SOT89-5

Advanced Power
Electronics Corp.
APPLICATION INFORMATION
OPERATION DESCRIPTION
self oscillating continuous-mode buck converter.
is no output from the current sense circuit. Under this condition, the output of CS comparator
is high. This turns on an internal switch and switches the SW pin low, causing current to flow
from V
and L1 to produce a voltage ramp (V
CS comparator switches low and the switch turns off. The current flowing on the R
decreases at another rate. When (V
mean current on the LED is determined by (
the number of external components while delivering LED current with ±5% accuracy, using a
1% sense resistor.
0.3V at DIM forces APE1630 to turn off the LED and the logic level at DIM must be at least
2.0V to turn on the full LED current. The frequency of PWM dimming ranges from 100Hz to
more than 20 kHz.
working. When a voltage applied to DIM falls below the threshold (0.3V nom.), the output
switch is turned off. The internal regulator and voltage reference remain powered during
shutdown to provide the reference for the shutdown circuit.
(TSD) protection and a thermal pad. The TSD protests the IC from over temperature (150°C).
Also the thermal pad enhances power dissipation. As a result, the APE1630 can handle a
large amount of current safely.
Setting nominal average output current with external resistor R
external current sense resistor (R
current which can be adjusted to a less one by dimming.
The device, in conjunction with the coil (L1) and current sense resistor (R
When input voltage V
The high-side current-sensing scheme and on-board current-setting circuitry minimize
The APE1630 allow dimming with a PWM signal at the DIM input. A logic level below
The DIM pin is pulled high current approximately 70µA. It can be floated at normal
Additionally, to ensure the reliability, the APE1630 is built with a thermal shutdown
This equation is valid when DIM pin is float. Actually, R
The nominal average output current in the LED(s) is determined by the value of the
IN
to ground, via R
S
, L1 and the LED(s). The current rises at a rate determined by V
IN
is first applied, the initial current in L1 and RS is zero and there
I
OUT
S
= 0.130/R
) connected between V
CSN
IN
-V
) across R
CSN
110 +
S
) < 110mV, the switch turns on again and the
(R
S
2
≧ 0.16Ω)
150
S
. When (V
mV) / R
IN
and CSN and is given by:
IN
S
= 130mV / R
S
-V
sets the maximum average
CSN
) > 150mV, the output of
S
.
S
), forms a
S
APE1630
IN
S
5