SLVSDD9 March 2017 TPS92692 , TPS92692-Q1
PRODUCTION DATA.
PIN | I/O | DESCRIPTION | |
---|---|---|---|
NAME | NO. | ||
COMP | 7 | I/O | Transconductance error amplifier output. Connect compensation network to achieve desired closed-loop response. |
CSN | 13 | I | Current sense amplifier negative input (–). Connect directly to the negative node of LED current sense resistor, RCS. |
CSP | 14 | I | Current sense amplifier positive input (+). Connect directly to the positive node of LED current sense resistor, RCS. |
DIM/PWM | 10 | I | External analog to PWM dimming command or direct PWM dimming input. The external analog dimming command between 1 V and 3 V is compared to the internal PWM generator triangle waveform to set LED current duty cycle between 0% and 100%. With PWM generator disabled, a direct PWM dimming command can be applied to control the LED current duty cycle and frequency. The analog or PWM command is used to generate an internal PWM signal that controls the GATE and PDRV outputs. Setting the internal PWM signal to logic level low, turns off switching, idles the oscillator, disconnects the COMP pin, and sets PDRV to VCSP. Connect to VREF when not used for PWM dimming. |
DM | 5 | I/O | Triangle wave spread spectrum modulation frequency, fm, programming pin. Connect a capacitor to GND to set the spread spectrum modulating frequency. Connect directly to GND to disable spread spectrum modulation of switching frequency. |
FLT | 3 | O | Open-drain fault indicator. Connect to VREF with a resistor to create active low fault signal output. Internal LED short circuit protection and auto-restart timer can enabled by directly connecting the pin to SS input. |
GATE | 19 | O | N-channel MOSFET gate driver output. Connect to gate of external main switching N-channel MOSFET. |
GND | 17 | — | Analog and Power ground connection pin. Connect to circuit ground to complete return path. |
IADJ | 9 | I | LED current reference input. Connect this pin to VCC with a 100-kΩ series resistor to set the internal reference voltage to 2.42 V and the current sense threshold, V(CSP-CSN) to 170.7 mV. The pin can be modulated by an external voltage source from 140 mV to 2.25 V to implement analog dimming. |
IMON | 8 | O | LED current report pin. The LED current sensed by CSP/CSN input is reported as VIMON = 14 × ILED × RCS. Bypass with a 1-nF ceramic capacitor connected to GND. |
IS | 18 | I | Switch current sense input. Connect to the switch sense resistor, RIS to set the switch current limit threshold based on the internal 250 mV reference. |
OV | 15 | I | Output voltage input. Connect a resistor divider from output voltage to GND to set output overvoltage and under-voltage protection thresholds. |
PDRV | 12 | O | Series dimming P-channel FET gate driver output. Connect to gate of external P-channel MOSFET to implement series FET PWM dimming and fault disconnect. |
RAMP | 11 | I/O | Programming input for internal PWM generator. Connect a capacitor to GND to set the triangle wave frequency for PWM generator circuit. Connect a 249-kΩ resistor to GND to disable the PWM generator and to set a fixed reference for direct external PWM dimming input. Do not allow this pin to float. |
RT | 6 | I/O | Oscillator frequency programming pin. Connect a resistor to GND to set the switching frequency. The internal oscillator can be synchronized by coupling an external clock pulse through a series capacitor with a value of 100 nF. |
SLOPE | 16 | I/O | Slope compensation input. Connect a resistor to GND to set the desired slope compensation ramp based on inductor value, input and output voltages. |
SS | 4 | I/O | Soft-start programming pin. Connect a capacitor to GND to extend the start-up time. Switching can be disabled by shorting this pin to GND. |
VCC | 20 | — | VCC (7.5 V) bias supply pin. Locally decouple to GND using a ceramic capacitor (with a value between 2.2-µF and 4.7-µF). Locate close to the controller. |
VIN | 1 | — | Input supply for the internal regulators. Bypass with a low-pass filter using a series 10-Ω resistor and 10- nF capacitor connected to GND. Locate the capacitor close to the controller. |
VREF | 2 | — | VREF (5 V) bias supply pin. Locally decouple to GND using a ceramic capacitor (with a value between 2.2-µF and 4.7-µF) located close to the controller. |
Thermal Pad | — | The GND pin must be connected to the exposed thermal pad for proper operation. This PowerPAD must be connected to PCB ground plane using multiple vias for good thermal performance. |