Diodes PAM2811 - Manual (Page 6)

PAM2811
Document number: DSxxxxx Rev. 1 - 0
6 of 13
www.diodes.com
November 2012
© Diodes Incorporated
PAM2811
A Product Line of
Diodes Incorporated
Application Information
The PAM2811 is a 4-channel programmable white-LED driver. It is capable of supplying 20mA per channel with a total of 80mA output current
available. LED brightness control of PAM2811 can be achieved with a Pulses signal.
Enable Input
The EN input is used to enable or disable the PAM2811. Pulling the EN pin higher than 1.5V will enable the device. For producing constant,
nonpulsating output current compare to conventional pulse width modulation (PWM) dimming scheme. The PAM2811 incorporates a 4-bit DAC for
brightness control to program the output current at 16 continuous steps: 20 to1.25mA. Table1 shows details for current setting.
Table 1 Current Setting
Data
Current
(mA)
Data
Current
(mA)
16 20.00 8 10.00
15 18.75 7 8.75
14 17.50 6 7.50
13 16.25 5 6.25
12 15.00 4 5.00
11 13.75 3 3.75
10 12.50 2 2.50
9 11.25 1 1.25
Page 2 shows the detail operation of 16-steps brightness control. When single-wire pulse counting dimming is used, the ready time is
recommended to be greater than 30µs for enabling the device, the pulse high time THI recommended to be greater than 0.5µs, and the pulse low
time T
LO
is recommended to be greater than0.5µs and less than 500µs. A constant current is sourced as long as the EN signal remains high. The
shutdown feature reduces quiescent current to less than 0.1µA.
LED Connection
The PAM2811 supports up to 4 white LEDs. The four LEDs are connected from VIN to LEDx respectively. If the LED is not used, it should be
connected to GND or open.
Over Temperature Protection
The PAM2811 equips over temperature protection. When the junction temperature (T
J
) exceeds +150°C, the current source turns off
automatically. The device will turn on again after the IC’s T
J
cools down under +120°C. Operating at absolute maximum temperature is not
recommended.