LM3559TLX National Semiconductor Corporation, LM3559TLX Datasheet - Page 15

• Manufacturer Part Number: LM3559TLX
• Description: Synchronous Boost Flash Driver With Dual 900 Ma High Side Current Sources 1.8a Total Flash Current
• Manufacturer: National Semiconductor Corporation

indicate mode turns off at the end of the flash pulse, and con-
tains the 8 intensity levels for the privacy indicator.
The intensity of the LEDs in privacy indicate mode is set by
PWM’ing the lowest Torch current level (28.125 mA). Bits
POWER AMPLIFIER SYNCHRONIZATION (TX1)
The TX1/TORCH/GPIO1 pin has a triple function. With Con-
figuration Register 1 Bit [7] = 0 (default) TX1/TORCH/GPIO1
is a Power Amplifier Synchronization input. This mode is de-
signed to reduce the flash LED current when TX1 is pulled
high (active high polarity) or low (active low polarity). When
the LM3559 is engaged in a Flash event and the TX1/TORCH
pin is pulled high, both LED1 and LED2 are forced into Torch
mode at the programmed Torch current setting. If TX1 is then
FIGURE 3. Privacy Indicate Timing
15
[2:0] of the Privacy Register allow for 8 different duty cycles
of 10%, 20%, 30%, 40%, 50%, 60%, 70%, and 80%. See
Table 14
timing for the Privacy Indicate Mode on ILED1 or ILED2.
pulled low before the Flash pulse terminates, the LED current
will return to the previous Flash current level. At the end of the
Flash timeout, whether the TX1/TORCH pin is high or low, the
current sources will turn off.
The polarity of the TX1 input can be changed from active high
to active low by writing a '0' to bit [5] of Configuration Register
1. With this bit set to ‘0’ the LM3559 will be forced into Torch
mode when TX1/TORCH is pulled low.
functionality of the TX1 Interrupt.
for Privacy Register Bit settings.
Figure 4
Figure 3
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