Click here for production status of specific part numbers. Evaluates: MAX20056B MAX20056B Evaluation Kit General Description Features The MAX20056B evaluation kit (EV kit) demonstrates the Input Voltage: 4.5V to 36V (Up to 50V Load Dump) MAX20056B, an integrated, 6-channel high-brightness Drives Six Strings of HB LEDs LED driver with very wide PWM dimming ratio and phase LED Current: 20mA to 120mA shifting for automotive displays. Demonstrates Both Phase-Shifted and Direct PWM The EV kit operates from a DC supply voltage from Dimming 4.5V to 36V and the switching frequency is set at Demonstrates Undervoltage Lockout and Output 400kHz. Spread-spectrum mode (SSM) is enabled for EMI improvement. The EV kit demonstrates direct Short Protection dim and phase-shifted pulse-width modulation (PWM) Demonstrates Cycle-by-Cycle Current Limit and dimming. The EV kit also demonstrates short-LED, open- Thermal-Shutdown Feature LED, and overtemperature-fault protection. Demonstrates 5V, 30mA LDO Output Capability For operation at switching frequencies other than 400kHz, Proven PCB and Thermal Design the external components should be chosen according to Fully Assembled and Tested the calculations in the MAX20056B IC data sheet. Note: The MAX20056B EV kit is identical to the MAX20056 EV kit, except for the U1 component. The photos and fig - Ordering Information appears at end of data sheet. ures indicate MAX20056, but there are no differences between this version and the standard version. MAX20056B EV Kit Photo 319-100310 Rev 0 2/19Evaluates: MAX20056B MAX20056B Evaluation Kit 10) Clip the current probe across the channel 1 HB Quick Start LED+ wire to measure the HB LED current. Required Equipment 11) Turn on the power supply and set to 12V. MAX20056B EV kit 12) Measure the voltage from each of the OUT PCB pads to PGND and verify the lowest voltage is 5V to 36V, 4A DC power supply approximately 1.1V. Two digital voltmeters (DVMs) 13) Measure the HB LED current using the current probe Six series-connected HB LED strings rated to no less and verify all channels. than 120mA Detailed Description of Hardware Current probe to measure the HB LED current The MAX20056B EV kit demonstrates the MAX20056B HB Procedure LED driver with an integrated step-up DC-DC preregulator followed by six linear current sinks for driving up to six strings The EV kit is fully assembled and tested. Follow the steps of LEDs. The preregulator switches at 400kHz and oper- below to verify board operation. Caution: Do not turn on ates as a current-mode-controlled regulator, providing up to the power supply until all connections are completed. 720mA for the linear circuit as well as overvoltage protection. 1) Verify that a shunt is installed across pins 1-2 on The cycle-by-cycle current limit is set by resistors R26 and jumper JU15 (device enabled). R27, while resistors R30 and R31 set the OVP voltage to 2) Verify that a shunt is installed across pins 1-2 on 29V. The preregulator power section consists of inductor jumper JU16 (400kHz switching frequency). L2, MOSFET N1, power-sense resistors R26 and R27, and 3) Verify that a shunt is installed across pins 1-4 on switching diode D2. The EV kit circuit operates from a 4.5V jumper JU13 (80mA LED current per string). DC supply voltage up to the HB LED forward string voltage. 4) Verify that a shunt is installed across pins 1-2 on The circuit handles load-dump conditions up to 50V. jumper JU14 (phase-shift operation enabled). 5) Verify that a shunt is installed across pins 1-2 on The EV kit circuit demonstrates ultra-low shutdown current when the EN pin of the device is pulled to ground by short- jumpers JU1JU6 (bleed resistors connected, all current sinks enabled). ing the EN PCB pad to ground. Each of the six linear current 6) Verify that jumpers JU7JU12 are open (LED strings sinks (OUT1OUT6) is capable of operating up to 48V, sink- not shorted). ing up to 120mA per channel. Each of the six channels linear 7) Connect the power supply to the IN PCB pad and current sinks is configurable for 120mA, 100mA, 80mA, or the power-supply ground to the PGND PCB pad. 20mA, or can be disabled independently. Jumpers JU1JU6 8) Connect a DVM across the OUT1 and PGND PCB provide the disable feature when the HB LED string is not pads. connected. See the Channel 1Channel 6 Current-Sink 9) Connect each HB LED string as follows: Disabling section. Resistors R4, R7, R8, R12, and jumper Channel 1: Connect HB LED string anode to the JU13 configure the linear current setting for the devices VOUT PCB pad and cathode to the OUT1 PCB pad ISET pin, which sets the HB LED string current. The EV kit features PCB pads to facilitate connecting HB LED strings Channel 2: Connect HB LED string anode to the for evaluation. The VOUT PCB pads provide connections VOUT PCB pad and cathode to the OUT2 PCB pad for connecting each HB LED strings anode to the DC-DC Channel 3: Connect HB LED string anode to the preregulator output. The OUT1OUT6 PCB pads provide VOUT PCB pad and cathode to the OUT3 PCB pad connections for connecting each HB LED strings cathode Channel 4: Connect HB LED string anode to the to the respective linear channels current sink. Additionally, VOUT PCB pad and cathode to the OUT4 PCB pad 2-pin headers (JU7JU12) provide convenient access to the VOUT and respective OUT connections when using a Channel 5: Connect HB LED string anode to the twisted-pair wiring connection scheme. On each header, pin VOUT PCB pad and cathode to the OUT5 PCB pad 1 provides access to the respective OUT connection and Channel 6: Connect HB LED string anode to the pin 2 provides access to the VOUT connection. Capacitors VOUT PCB pad and cathode to the OUT6 PCB pad C7, C8, C10, C11, C14, and C15 are included on the design Maxim Integrated 2 www.maximintegrated.com