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OCP8178
White LED Driver With Digital and PWM Brightness Control
General Description
With a 40-V rated integrated switch FET, the
OCP8178 is a boost converter that drives LEDs in
series. The boost converter runs at 600kHz fixed
switching frequency to reduce output ripple, improve
conversion efficiency, and allows for the use of small
external components.
The default white LED current is set with the
external sensor resistor Rset, and the feedback voltage
is regulated to 200mV, as shown in the typical
application. During the operation, the LED current can
be controlled using the 1-wire digital interface through
the CTRL pin. Alternatively, a pulse width modulation
(PWM) signal can be applied to the CTRL pin through
which the duty cycle determines the feedback
reference voltage. In either digital or PWM mode, the
OCP8178 does not burst the LED current; therefore, it
does not generate audible noises on the output
capacitor. For maximum protection, the device features
integrated open LED protection that disables the
OCP8178 to prevent the output voltage from exceeding
the IC's absolute maximum voltage ratings during open
LED conditions.
The OCP8178 is available in a space-saving,
2mm × 2mm DFN package with thermal pad.
Features
2.7V to 5.5V Input Voltage Range
38V Open LED Protection
200mV Reference Voltage
Flexible Digital and PWM Brightness Control
Built-in Soft Start
Up to 90% Efficiency
2mm × 2mm × 0.8mm DNF2X2-6L(6-pinDFN )
Package With Thermal Pad
Applications
Cellular Phones
Portable Media Players
Ultra Mobile Devices
GPS Receivers
White LED Backlighting for Media Form Factor
Display
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Rev. 1.6 Feb .27, 2018
源于灿瑞 磁传天下

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Pin Configuration
DFN2X2-6L
OCP8178
Pin
Name
VIN
SW
GND
FB
COMP
CTRL
Thermal Pad
Figure 1, Pin Assignments of OCP8178
Pin No.
DFN-6pins
6
4
3
1
2
5
I/O Pin Function
I
The input supply pin for the IC. Connect VIN to a supply
voltage between 2.7V and 5.5V.
This is the switching node of the IC. Connect the inductor
O between the VIN and SW pin. This pin is also used to sense
the output voltage for open LED protection
I Ground
I
Feedback pin for current. Connect the sense resistor from FB
to GND.
O
Output of the transconductance error amplifier. Connect an
external capacitor to this pin to compensate the converter.
Control pin of the boost converter. It is a multi-functional pin
I which can be used for enable control, PWM and digital
dimming.
The thermal pad should be soldered to the analog ground
plane. If possible, use thermal via to connect to ground plane
for ideal power dissipation.
Page2 3
Rev. 1.6 Feb .27, 2018
源于灿瑞 磁传天下

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Typical Application Circuit
OCP8178
Figure 2, Typical Application Circuit of OCP8178
Ordering Information
Part Number
Maximum
VOUT
OCP8178VAD 38V
VFB
200mV
Package
Type
DFN2X2-6L
Package Qty Temperature
7-in reel
3000pcs/reel
-4085
Eco
Plan
Green
Lead/Ball
Finish
NIPDAU
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Page3 3
Rev. 1.6 Feb .27, 2018
源于灿瑞 磁传天下