PT16972 4-Channel 100mA LED Driver with DC-DC Controller DESCRIPTION PT16972 is a 4-Channel constant current LED driver with current-mode switching DC-DC controller. The output current range can be externally programmed for 10mA~100mA per channel. Also, the output voltage can be up to 36V. The PT16972 supports the boost, coupled-inductor boost-buck or SEPIC topologies and operates in an adjustable switching frequency between 200kHz and 2.1MHz. High PWM dimming ratio 2500:1 can be achieved by internal fast response time 2μS with 200Hz PWM dimming frequency. The PT16972 allows to detect and manage the open and shorted LED faults and to let unused channel floating. Also, the device includes output over-voltage protection, thermal shutdown protection and internal power MOSFET over-current protection. Two fault indication pins are provided to separate the failure mode. FEATURES • • • • • • • • • • • • • • • 6V~36V Input Voltage Output Voltage Up to 36V Output Current Range 10mA~100mA/CH ±1% LED Current Matching at 20mA or Higher Programmable Frequency 200KHz~2.1MHz 2uS Minimum PWM Dimming on Time Support Boost, Coupled-Inductor Boost-Buck or SEPIC Topologies Selectable Output Channels Low Standby Current Adjustable Internal MOSFET Current Limitation and Soft-Start LED Open / Short Protection Output Over-Voltage Protection Thermal Shutdown Protection at 150℃ Two Fault Indication Pins TSSOP24 (173mil) with Exposed PAD Package APPLICATIONS • Automotive Navigation LCD Panel Backlight • Desktop and Notebook LCD Panel Backlight • PDAs Panel Backlight BLOCK DIAGRAM Tel: 886-66296288‧Fax: 886-29174598‧ http://www.princeton.com.tw‧2F, 233-1, Baociao Road, Sindian, Taipei 23145, Taiwan PT16972 TYPICAL APPLICATION Boost Configuration SEPIC Configuration V1.0 2 October 2011 PT16972 ORDER INFORMATION Valid Part Number PT16972 Package Type HTSSOP24 Top Code PT16972-HT PIN CONFIGURATION V1.0 3 October 2011 PT16972 PIN DESCRIPTION Pin Name LED1 LED2 LED3 LED4 /FLT1 /FLT2 SET ISET /EN VDD NC VIN PWM AGND RT COMP SC ILIM SST OVP PGND PGND SW SW V1.0 Description LED String Driver Output 1. LED String Driver Output 2. LED String Driver Output 3. LED String Driver Output 4. Fault Signal Open Drain Output. /FLT1 will be low when LED open or shorted is detected. Fault Signal Open Drain Output. /FLT2 will be low when thermal shutdown or output over-voltage is detected. Channel Selection. Pin logic level will set the output channels: SET=0 or floating, 4 channels are used; SET=1, LED4 is not used. An internal 100kΩ pull-low resistor is used. LED Current Setting. A resistor to AGND to program the output current per channel. Enable Control. /EN=0 or floating, the device is turn on. /EN=1, the device is turned off. An internal 100KΩ pull-low resistor is used. Internal 5V Regulator Output. Bypass to AGND with a 10μF ceramic capacitor. Non-Connection. Input Supply Voltage. External PWM Dimming Input. PWM=0 or floating, the switching and the current generators are turned off. PWM=1, the switching and the current generators operate normally. An internal 100KΩ pull-low resistor is used. Analog Ground. Switching Frequency Setting. A resistor to AGND which programs the switching frequency between 200KHz and 2.1MHz. Error Amplifier Output pin. Tie the external compensation network. Slope Compensation Setting. A resistor between this pin and AGND is needed. It can avoid sub-harmonic instability. Internal Switch Current Limit Setting. A resistor to AGND to program the current limit level of power MOSFET. Soft-Start. Connect a capacitor to AGND to set the soft-start time. Over Voltage Protection. When VOVP>1.2V, the over-voltage protection occurs. Power Ground. Source of internal power MOSFET. Power Ground. Source of internal power MOSFET. Switching pin. Drain of internal power MOSFET. Switching pin. Drain of internal power MOSFET. 4 Pin No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 October 2011