Evaluates: MAX20090 MAX20090 Evaluation Kit Procedure General Description The EV kit is fully assembled and tested. Follow the steps The MAX20090 evaluation kit (EV kit) provides a proven below to verify board operation. Caution: Do not turn on design to evaluate the MAX20090 automotive high-volt- power supply until all connections are made. age, high-brightness LED (HB LED) controller. The EV kit is set up for boost and buck-boost configurations and 1) Verify that all jumpers (J1J4) are in their default operates from a 6V to 18V DC supply voltage. The EV kit positions, as shown in Table 1. is configured to deliver up to 1A to one string of LEDs. 2) Connect the positive terminal of the 12V supply to the The total voltage of the string can vary from 3V to 36V. IN PCB pad and the negative terminal to the nearest The anode of the LED string should be connected to GND1 PCB pad. the LED+ terminal. The cathode of the LED string can 3) Connect the LED string across the LED+ and be connected either to PGND (boost mode) or IN (buck- LED- PCB pads on the EV kit for buck-boost boost mode). In the case of boost mode, the input voltage configuration. For boost configuration, connect the should not exceed the LED string voltage. LED string across the LED+ and GND2 PCB pads on the EV kit. The LED string voltage should be higher Features than the input voltage in this configuration. Configured for a Boost and Buck-Boost Mode 4) Clip the current probe on the wire connected to the Analog Dimming Control LED string. Proven PCB Layout 5) Turn on the DC power supply. Fully Assembled and Tested 6) Verify that the LEDs turn on. Quick Start 7) Verify that the oscilloscope displays approximately 1A. Required Equipment Detailed Description MAX20090 EV kit The MAX20090 EV kit provides a proven design to 12V, 5A DC power supply evaluate the MAX20090 high-voltage HB LED driver with integrated high-side current sense. The EV kit is set up for A series-connected LED string rated at 1A boost and buck-boost configurations and operates from a Oscilloscope with a current probe 6V to 18V DC supply voltage. The EV kit is configured to deliver up to 1A to a series LED string. The string-forward voltage can vary from 3V to 36V. Ordering Information appears at end of data sheet. 19-8750 Rev 0 12/16Evaluates: MAX20090 MAX20090 Evaluation Kit Table 1. MAX20090 EV Kit Jumper Descriptions (J1J4) SHUNT JUMPER DESCRIPTION POSITION Connects the PWMDIM pin of the device to VCC through a 4.99k resistor. 1-2* The LEDs turn on when the input voltage goes above the UVLO level if J4 is open. Connects the PWMDIM pin to ground through a 4.99k resistor. Need to apply an external J1 2-3 PWM signal or a DC voltage on the PWMDIM PCB pad to turn on the LEDs when the input voltage on IN is in the operating range. Open Connects the PWMDIM pin to ground if J4 is installed otherwise, PWMDIM pin is unconnected. Connects VCC to the ICTRL pin. LED current is at the maximum value of 1.1A in this 1-2 configuration. ICTRL pin is now connected to a voltage-divider from VCC to ground. Adjusting R2 allows J2 2-3* programming the LED current from 0 to 1.1A. Disconnects the ICTRL pin of the device from the external voltage-divider on the VCC pin. Open Allows the user to apply an external voltage to set the LED current level. 1-2* Connects the FLT pin to VCC through a 10k resistor. J3 Open No pullup on FLT pin. Open* PWMDIM pin is controlled by the jumper J1 setting only. J4 Analog voltage on PWMDIM pin controlled by the voltage-divider of R13 and R18. 1-2* Adjust R18 to vary the analog voltage on PWMDIM. Jumper J1 should be in default position. *Default position. This can be done by installing the shunt on J1 across Analog Dimming Control (ICTRL) pins 2-3, without applying any external voltage on the When J2 is installed across pins 1-2, the LED current is PWMDIM PCB pad. The PWMDIM pin can also be con- set at the maximum current. The ICTRL pin is connected trolled by an analog DC voltage on the PWMDIM pin. In to VCC and in this case, the LED current is given by the this case, the dimming frequency is internally set at 200Hz. following equation: This can be achieved by installing the shunt on J1 across 220mV pins 1-2, the shunt on J4 installed across pins 1-2, and I = LED adjusting potentiometer R18. The dimming duty cycle can R14 be adjusted from 0 to 100% duty cycle by adjusting the When J2 is installed across pins 2-3, the ICTRL pin is voltage on the PWMDIM pin from 0.2V to 3.25V. connected to the voltage-divider of R1 and R2, which sets Alternatively, PWM dimming can be achieved by applying the voltage at ICTRL a DC voltage between 0.2V and 3.3V on the PWMDIM In the case of the EV kit, I is set to 1A. If V < PCB pad, with J1 and J4 open. LED ICTRL 1.2V, then V sets the LED current level. ICTRL Alternatively, the analog dimming can be controlled by Ordering Information removing the shunt on J2 and applying a voltage between PART TYPE 0 and 5.5V on the ICTRL PCB pad on the EV kit. MAX20090EVKIT EV Kit Pulse-Dimming Input (PWMDIM) Denotes RoHS compliant. Pulse dimming can be achieved by applying a pulsating voltage source on the PWMDIM PCB pad on the EV kit. When PWMDIM is pulled low, DIMOUT is pulled high and the pulse-width-modulated (PWM) switching is disabled. 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