Texas Instruments Evaluation Module for TPS65708 TPS65708EVM-587 TPS65708EVM-587 데이터 시트
제품 코드
TPS65708EVM-587
Connector and Test Point Descriptions
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4.1.21
J20 PWM_LED/GND
J20, pin 1 is the PWM input connection for the LED current sink. Use a signal generator, for example, to
drive this input. The PWM dimming frequency can be up to 50 kHz, and the duty cycle should be in the
range of 5% to 100%. At a 100% duty cycle, the LED current is 7.5 mA. Average LED current decreases
with a decreasing duty cycle. In the default EVM configuration, there is a 100-k
drive this input. The PWM dimming frequency can be up to 50 kHz, and the duty cycle should be in the
range of 5% to 100%. At a 100% duty cycle, the LED current is 7.5 mA. Average LED current decreases
with a decreasing duty cycle. In the default EVM configuration, there is a 100-k
Ω
resistor (R5) assembled
between the PWM and GND to terminate the PWM input. SMA connector J22 is also connected to the
PWM input. Either J20 or J22 can be used.
PWM input. Either J20 or J22 can be used.
4.1.22
J21 LED_ANODE / GND
J21, pin 1 is connected to the anode of LED D1. In the default EVM configuration, the LED anode is
supplied from VIN with resistor R7. An external LED power supply can be connected between J22 pin 1
(LED_ANODE) and J22 pin 2 (GND).
supplied from VIN with resistor R7. An external LED power supply can be connected between J22 pin 1
(LED_ANODE) and J22 pin 2 (GND).
Note: R7 must be removed if an external LED power supply is used.
4.1.23
J22 PWM_LED / GND (SMA)
J22 is an SMA connector that is connected to the PWM input connection of the LED current sink. Use a
signal generator, for example, to drive this input. The PWM dimming frequency can be up to 50 kHz, and
the duty cycle should be in the range of 5% to 100%. At a duty cycle of 100%, the LED current is 7.5 mA.
Average LED current decreases with a decreasing duty cycle. In the default EVM configuration, there is a
100-k
signal generator, for example, to drive this input. The PWM dimming frequency can be up to 50 kHz, and
the duty cycle should be in the range of 5% to 100%. At a duty cycle of 100%, the LED current is 7.5 mA.
Average LED current decreases with a decreasing duty cycle. In the default EVM configuration, there is a
100-k
Ω
resistor (R5) assembled between the PWM and GND to terminate the PWM input. J20 is also
connected to the PWM input. Either J20 or J22 can be used.
4.1.24
JP1 ISINK / LED CATHODE
JP1 is a jumper that is connected between the LED CATHODE and the input of the LED current sink,
ISINK. Placing a shorting bar on JP1 directly connects the the LED cathode to the input of the LED current
sink.
ISINK. Placing a shorting bar on JP1 directly connects the the LED cathode to the input of the LED current
sink.
JP1 can be opened, and an amp meter or current probe of a scope can be connected between the pins of
JP1 to measure the LED current.
JP1 to measure the LED current.
4.1.25
JP2 MODE
This jumper enables/disables the power-saving mode under light load conditions. Shorting jumper JP2
between the center pin and the PWM disables power-save mode; if the power-save mode is disabled, the
dc-dc converters DCDC1 and DCDC2 operate in forced PWM mode over the entire load current range.
Shorting the jumper between the center pin and the PWM enables power-save mode. The device
operates in power-save mode under light load conditions. See the
between the center pin and the PWM disables power-save mode; if the power-save mode is disabled, the
dc-dc converters DCDC1 and DCDC2 operate in forced PWM mode over the entire load current range.
Shorting the jumper between the center pin and the PWM enables power-save mode. The device
operates in power-save mode under light load conditions. See the
) for a
detailed description of this configuration.
A 1-M
Ω
pull-down resistor is connected between GND and MODE. By removing JP2, the converter
operates in power-save mode under light load conditions.
6
TPS65708EVM
SLVU402 – October 2010
Copyright © 2010, Texas Instruments Incorporated