AP5726WG-7 Diodes Inc, AP5726WG-7 Datasheet - Page 10

• Manufacturer Part Number: AP5726WG-7
• Description: Switching Converters, Regulators & Controllers WH LED STEP-UP DC/DC CONV 2-6 LED
• Manufacturer: Diodes Inc
• Series: -r

Specifications of AP5726WG-7

• Constant Current: Yes
• Constant Voltage: -
• Topology: PWM, Step-Up (Boost)
• Number Of Outputs: 1
• Internal Driver: Yes
• Type - Primary: Backlight
• Type - Secondary: White LED
• Frequency: 1MHz ~ 1.4MHz
• Voltage - Supply: 2.7 V ~ 5.5 V
• Voltage - Output: -
• Mounting Type: Surface Mount
• Package / Case: SOT-23-6
• Operating Temperature: -40°C ~ 85°C
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Applications Information
Open-Circuit Protection
In the cases of output open circuit, when the LEDs are disconnected from the circuit or the LEDs fail, the
feedback voltage will be zero. The AP5726 will then switch at a high duty cycle resulting in a high output voltage,
which may cause the SW and OVP pin voltage to exceed the voltage rating of these pins. The OVP pin monitors
the output voltage. If the output voltage reaches the over voltage protection threshold at the OVP pin (Figure 2),
the over voltage protection is activated and SW pin stops switching.
Dimming Control
There are four different types of dimming control circuits:
1. Using a PWM Signal to EN Pin
With the PWM signal applied to the EN pin, the AP5726 is turned on or off by the PWM signal. The LEDs operate
at either zero or full current. The average LED current increases proportionally with the duty cycle of the PWM
signal. A 0% duty cycle will turn off the AP5726 and corresponds to zero LED current. A 100% duty cycle
corresponds to full current. The typical frequency range of the PWM signal is below 2kHz.
AP5726
Document number: DS31845 Rev. 3 - 2
V
IN
1uF
Figure 2. LED Driver with Open-Circuit Protection
C
(Continued)
IN
EN
V
AP5726
22uH
IN
GND
L1
www.diodes.com
SW
OVP
FB
10 of 17
D1
WHITE LED STEP-UP CONVERTER
x
x
15
R
SET
C
OUT
1uF
AP5726
© Diodes Incorporated
July 2010