LP3936SL National Semiconductor, LP3936SL Datasheet - Page 16

• Manufacturer Part Number: LP3936SL
• Manufacturer: National Semiconductor

Specifications of LP3936SL

• Operating Supply Voltage (typ): 3.3/5V
• Number Of Segments: 6
• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Industrial
• Package Type: LAM CSP
• Pin Count: 32
• Mounting: Surface Mount
• Operating Supply Voltage (min): 3V
• Operating Supply Voltage (max): 6V
• Lead Free Status / Rohs Status: Compliant

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RGB LED Driver
The RGB driver has three outputs that can independently
drive one RGB LED or three LEDs of any kind. User has
control over the following parameters separately for each
LED:
RGB_START is the master enable control for the whole RGB
function. The internal PWM and blinking control can be
disabled by setting the RGB_PWM control LOW. In this case
the individual enable controls can be used to switch outputs
on and off. RGB_EN input can be used for external hardware
PWM control. RGB_EN input can be used as direct on/off or
brightness (PWM) control. If RGB_EN input is not used, it
must be tied to V
of RGB LED external PWM control is 1 MHz.
In the normal PWM mode the R, G and B switches are
controlled in 3 phases (one phase per driver). During each
phase the peak current set by external resistor is driven
through the LED for the time defined by DUTY setting
(0 µs–50 µs). As a time averaged current this means
0%–33% of the peak current. The PWM period is 150 µs and
the pulse frequency is 6.67 kHz in normal mode.
• ON and OFF (start and stop time in blinking cycle)
Normal Mode PWM Waveforms at different duty
DD_IO
. Recommended maximum frequency
settings
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RGB PWM Operating Principle
16
• DUTY
• SLOPE
• ENABLE
The main blinking cycle is controlled with 2-bit CYCLE con-
trol (0.25 / 0.5 / 1.0 / 2.0s).
In the FLASH mode all the outputs are controlled in one
phase and the PWM period is 50 µs. The time averaged
FLASH mode current is three times the normal mode current
at the same DUTY value.
Blinking can be controlled separately for each output. On
and OFF times determine, when a LED turns on and off
within the blinking cycle. When both ON and OFF are 0, the
LED is on and doesn’t blink. If ON equals OFF but is not 0,
the LED is permanently off.
Example Blinking Waveforms
(PWM brightness control)
(dimming slope)
(direct enable control)
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