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PDF PT4303 Data sheet ( Hoja de datos )
| Número de pieza | PT4303 | |
| Descripción | 1x/1.5x Auto-Adjust Charge Pump 4-Channel White LED Driver | |
| Fabricantes | Powtech | |
| Logotipo |  |
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PT4303
1x/1.5x Auto-Adjust Charge Pump
4-Channel White LED Driver with Two Dimming Modes
GENERAL DESCRIPTION
The PT4303 is a 4-channel 1x/1.5x auto-adjust charge
pump white LED driver with two dimming modes.
Auto-adjust charge pump achieves high efficiency for
Li-Ion battery supply. The two LED dimming modes
enable users to dim the four LEDs all together or
individually. Only a few external components (two
flying capacitors and two filter capacitors at VIN and
VOUT) are needed, which makes the PT4303 ideally
suited for mobile applications.
The current through the LED can be set by an external
resistor. The four LEDs can be turned on and off
individually or in a group of two to four through the
two control terminals, which can also be used to dim
the LEDs by applying PWM control signals.
Built-in soft-start circuit prevents the inrush current
from the power supply during power on and 1x/1.5x
mode change. The thermal shutdown and current
limiter prevent the PT4303 from being damaged by a
high-level current through it. A shutdown current of less
than 1uA makes the battery last longer. The PT4303 is
available in QFN-16 package.
FEATURES
z 3V-5.5V input voltage
z 1x/1.5x auto-adjust charge pump
z Set LED current by external resistor
z Dimming LED by PWM signal through 2
control terminal
z LED fault detection
z <3% current mismatch
z No inductor
z Less than 1uA shutdown current
z Built-in soft-start and soft mode decision
APPLICATIONS
z Cell phones
z Laptop computers and PDAs
z Digital cameras
z Small LCD displays
ORDERING INFORMATION
PACKAGE
TEMPERATURE
RANGE
ORDERING PART
NUMBER
QFN-16（3x3）
-40 oC to 85 oC
PT4303EQFN
Note:
xxxxxX
Assembly Factory Code
Lot Number
TYPICAL APPLICATION CIRCUIT
C1 1uF C2 1uF
TRANSPORT
MEDIA
Tape and Reel
3000 units
MARKING
PT4303
xxxxxX
C1 1uF C2 1uF
3V to 5.5V
CIN 1uF
Control
bit 0-1
C1N C1P C2N C2P
VIN VOUT
EN
CTRL0
CTRL1
GND
LED1
LED2
LED3
LED4
ISET
COUT
1uF
RSET(24K)
3V to 5.5V
CIN 1uF
Control
bit 0-1
C1N C1P C2N C2P
VIN VOUT
EN
CTRL0
CTRL1
GND
LED1
LED2
LED3
LED4
ISET
COUT
1uF
RSET(24K)
Figure 1. Li-Ion Battery Driving 4 White LEDs
Figure 2. Li-Ion Battery Driving 3 White LEDs
China Resources Powtech (Shanghai) Limited
PT4303_DS Rev EN_1.1
WWW.CRPOWTECH.COM
Page 1
1 page  
PT4303
1x/1.5x Auto-Adjust Charge Pump
4-Channel White LED Driver with Two Dimming Modes
OPERATION DESCRIPTION
The PT4303 uses a 1.5x/1x charge pump and current sink to drive the 4 channels white LED. 1x charge pump can
achieve high efficiency for high input voltage, 1.5x charge pump guarantees the enough current through the LED for
low level input voltage. The current through the LED can be pre-set by an external resistor. The four LEDs can be
turned on and off individually or in a group of two to four through the two control terminals, which can also be used
to dim the LEDs by applying PWM control signals.
z Mode Decision
z Over Load Protection
The PT4303 uses a 1.5x/1x charge pump. The switching
between the two modes is through a “smart” control. The
PT4303 constantly senses the voltage at D1 to D4 ( the one
with the lowest voltage will be selected), the input and output
voltage. Based on this information, the PT4303 determines
which charge pump mode to be selected in order to achieve
the maximum efficiency. User intervention isn’t needed to
complete this process.
z Fault LED Detection
The PT4303 goes through an LED current detection sequence,
when the chip is powered on or when OVP is trigged. If a
channel is unused and floating, or if a channel has a failed
LED to become open circuit, the PT4303 automatically
changes the sense point to a channel that has normal operation
to maintain the maximum efficiency.
z Soft Start
A soft start circuit is turned on at power on or mode switching
process in order to reject the inrush current from VIN. The
circuit sets the current limit low initially and increases the
input current gradually in discrete steps. The soft start time is
dependent on the input level, the output current and the LED
forward voltage.
Control Bits
CTRL0
CTRL1
LED1
0 0 ON
0 1 ON
1 0 ON
1 1 OFF
The PT4303 employs the over-load protection to avoid the
high current from VIN. Whenever the input current rises
above the threshold, the PT4303 decreases the input current to
protect the chip and battery.
z Over Voltage Protection
The PT4303 employs an over voltage protection circuit to
detect the output voltage in 1.5x mode. Whenever the output
voltage level rises above the threshold of 1.5x mode, the
PT4303 shuts down the charge pump until the output voltage
falls blew the threshold.
z Thermal Shutdown
When the chip temperature rises above the 160 oC, the
PT4303 shuts down the charge pump and the current sink to
protect the chip from thermal damage.
z LED Current On/Off Setting
Each LED to be turned on or off can be set by 2 control bits.
The control scheme is shown in the following table.
Output Status
LED2
LED3
ON OFF
ON ON
ON ON
OFF OFF
LED4
OFF
ON
OFF
OFF
Table.1 LED’s On/Off and the Control Bits
China Resources Powtech (Shanghai) Limited
PT4303_DS Rev EN_1.1
WWW.CRPOWTECH.COM
Page 5
5 Page | ||
| Páginas | Total 10 Páginas | |
| PDF Descargar | [ Datasheet PT4303.PDF ] | |
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