TLD5097EL_15 Datasheet, PDF (17/41 Pages) Infineon Technologies AG – Multitopology LITIX Power DC/DC Controller IC

Infineon® LITIX™ Power
TLD5097EL
Enable and Dimming Function
7
Enable and Dimming Function
Description
The enable function powers ON or OFF the device. A valid logic LOW signal on enable pin EN/PWMI powers OFF
the device and current consumption is less than I_{q_OFF} (Parameter 7.2.8). A valid logic HIGH enable signal on
enable pin EN/PWMI powers on the device. The enable function features an integrated pull down resistor
which ensures that the IC is shut down and the power switch is OFF in case the enable pin EN is left open.
In addition to the enable function described above, the EN/PWMI pin detects a pulse width modulated (PWM)
input signal that is fed through to the internal gate driver. The EN/PWMI enables and disables the gate driver
for the main switch during PWM operation. PWM dimming an LED is a commonly practiced dimming method
and can prevent color shift in an LED light source.
The enable and PWM input function share the same pin. Therefore a valid logic LOW signal at the EN/PWMI pin
needs to differentiate between an enable power OFF or an PWM dimming LOW signal. The device
differentiates between enable OFF and PWM dimming signal by requiring the enable OFF at the EN/PWMI pin
to stay LOW for the Enable Turn OFF Delay Time (t_EN,OFF,DEL Parameter 7.2.6).
IN
14
Enable
LDO
Microcontroller
EN / PWMI
13
Enable / PWMI
Logic
Enable / PWMI
Gate
Driver
IVCC
1
SWO
2
Figure 7-1 Block Diagram and Simplified Application Circuit Enable and LED Dimming
Data Sheet
17
Revision 1.0
2015-03-12