In addition to its popular line-up of RS232/485 interface transceivers, Zywyn now offers a complete family of LED drivers for backlighting and now industrial lighting applications. The ZD831/832 types are transformerless AC-DC constant current LED drivers, while the ZD850 is a 1.5A high power device.
The ZD850 is a constant off-time, high power LED driver IC using a Buck Converter Topology that is capable of driving up to 1.5A of output current. It operates from an input voltage range of 4VAC to 16VAC or 5VDC to 27VDC and generates a regulated programmable constant output current for high power LEDs. A patent pending design technique with AC/ DC bridge rectifi er, linear regulator and internal high voltage NDMOS power switch has been designed on-chip to reduce component count by eliminating the need for an external power switch and diode bridge. Based on high effi cient PFM control design, the minimum Off-Time in the controlled frequency range is set at a typical 1.5μs, allowing a good LED current regulation over a wide range of supply voltage with respect to using conventional transformers or E-transformers. Built-in thermal and over-voltage circuitry protects the powertransistors from excessive power dissipation.
The ZD850 is available in a thermally enhanced 16-pin exposed TSSOP green package.
The ZD831/ZD832 are high voltage, TransformerFree™ AC-DC constantcurrent drivers for driving a string of white or RGB LEDs in series. The input voltage range (85VAC to 120VAC for ZD831 and 85VAC to 170VAC, or 170VAC to 240VAC for ZD832) generates a programmable constant output current. The high operating voltage of ZD831/ZD832, along with linear control architecture eliminates the need for an external inductor, transformer and rectifying diode bridge. The output current level is set by a single resistor and can be set as high as 30mA. Dimming control can be accomplished by using pulse-width modulation signal with varying duty cycle on the PWM pin or by applying an analog DC voltage on the ISET pin. Thermal and over-voltage circuitry protects the internal power transistors from excessive power dissipation.
The ZD831/ZD832 are available in a thermally enhanced 20-pin exposed TSSOP green package.
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