Linear’s LT3597 is a 60V three-way step-down LED driver that provides 10,000:1 digital PWM dimming at 100Hz. Each channel can drive up to 10 LEDs. The switching frequency can be programmed between 200kHz and 1MHz. Adaptive control output For best efficiency, 2% LED current matching between channels, open LED reporting, short LED protection, programmable LED current and programmable temperature protection. The LT3597 can be used in LED signal boards, single color, multicolor and full color LED displays , large screen Display LED backlight and automotive, industrial and medical displays. This article introduces the main features of LT3597, block diagram and various application circuit diagrams.
The LTR3597 is a 60V triple step-down LED driver capable of achieving 10,000:1 digital PWM dimming at 100Hz with fast NPN current sources driving up to 10 LEDs in each channel. LED dimming can also be achieved via analog control of the CTRL1-3 pin.
The step-down switching frequency is programmed between 200kHz and 1MHz. The frequency is also synchronizable to an external clock. The LT3597 provides maximum LED brightness while adhering to manufacturers’ specifications for thermal derating. The derate temperature is programmed by placing a negative temperature coefficient (NTC) resistor on the master control pin.
The LT3597 adaptively controls VOUT in order to achieve optimal efficiency. Other features include: 2% LED current matching between channels, open LED reporting, shortened LED protection, programmable LED current, and programmable temperature protection.
LT3597 main features:
Three 100mA Buck Regulators, Each Drives Up to 10 LEDs with Fast NPN Current Sources
Fast Current Sources for <1μs Pulse Widths (10,000:1 True Color PWM™ Dimming at 100Hz)
LEDs Disconnected in Shutdown
Adaptive VOUT for Increased Efficiency
6V to 60V Input Voltage Range
±2% LED Current Matching
External Resistor Sets LED Current for Each Channel
Internal Compensation and Soft-Start
Programmable Switching Frequency (200kHz to 1MHz)
Synchronizable to External Clock
Open LED Detection and Reporting
Shorted LED Pin Protection and Reporting
Programmable LED Thermal Derating
Programmable Temperature Protection
5mmx 8mm Thermally Enhanced QFN Package with a 0.6mm High Voltage Pin Spacing
LED Billboards and Signboards
Mono, Multi, Full-Color LED Displays
Large Screen Display LED Backlighting
Automotive, Industrial, and Medical Displays
Figure 1. LT3597 block diagram
Figure 2. LT3597 three-way RGB single-pixel 100mA LED driver circuit diagram
Figure 3. LT3597 48V 1MHz step-down 100mA RGB LED driver circuit diagram
Figure 4. LT3597 48V 1MHz step-down 10W 100mA RGB LED driver circuit diagram (3.6V LED)
Figure 5. LT3597 24V 200kHz triple step-down 100mA RGB LED driver circuit diagram
Figure 6. LT3597 48V 1MHz triple step-down 20mA RGB LED driver circuit diagram
For details, see: