AP8800SG-13 Diodes Inc, AP8800SG-13 Datasheet - Page 4

• Manufacturer Part Number: AP8800SG-13
• Description: IC LED DRIVER HIGH BRIGHT 8SOIC
• Manufacturer: Diodes Inc
• Type: HBLED Driverr

Specifications of AP8800SG-13

• Constant Current: Yes
• Topology: PWM, Step-Down (Buck)
• Number Of Outputs: 1
• Internal Driver: Yes
• Type - Primary: Backlight
• Type - Secondary: High Brightness LED (HBLED)
• Frequency: 600kHz
• Voltage - Supply: 8 V ~ 28 V
• Voltage - Output: 28V
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Operating Temperature: -40°C ~ 85°C
• Current - Output / Channel: 350mA
• Internal Switch(s): Yes
• Efficiency: 92%
• High Level Output Current: 350 mA
• Operating Supply Voltage: 8 V to 28 V
• Maximum Supply Current: 30 uA
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: AP8800SGDITR

Application Information
LED Current Control
The LED current is controlled by the resistor RSET in Figure 1.
If the CTRL pin is floating and at a nominal voltage of VREF, the external current sense resistor RSET (greater than 0.3 Ω) is
connected between VIN and SET and defines the nominal average output current in the LED(s) as:
If the CTRL pin is driven by an external voltage (lower than 2.5V), the average LED current in this case is:
The graph in figure 3 gives values of nominal average output current for several values of current setting resistor (RSET) in
the typical application circuit shown on Figure 1, for different voltages applied on the CTRL pin.
AP8800
Document number: DS31764 Rev. 5 - 2
I
I
LED
LED
=
=
V
V
400
350
300
250
200
150
100
V
R
CTRL
50
REF
0
THD
SET
0
R
V
0.15 0.3 0.45 0.6 0.75 0.9 1.05 1.2 1.35 1.5 1.65 1.8 1.95 2.1 2.25 2.4 2.55 2.7 2.85
THD
SET
0.3
0.3
0.33
0.39
0.39
0.47
0.47
0.56
0.56
0.56
0.68
0.68
0.68
0.75
Fig. 3 LED Current setting vs. R
0.82
0.82
0.82
1
1
1
LED current Versus RSET and VCTRL
1.2
1.2
RSET value [Ohms]
1.2
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1.5
1.5
1.5
4 of 11
350mA LED STEP-DOWN CONVERTER
2
2
2
SET
and V
CTRL
3
3
3
3
AP8800
LED current @
VCTRL = 1.25V
LED current @
VCTRL = 2.5V
LED current @
VCTRL = 0.625V
© Diodes Incorporated
March 2011