Product Description
The CAT4240 is a DC-DC step-up converter that delivers an accurate constant current ideal for driving LEDs. Operation at a fixed switching frequency of 1 MHz allows the device to be used with small value external ceramic capacitors and inductor. LEDs connected in series are driven with a regulated current set by the external resistor R1. The CAT4240 high-voltage output stage is perfect for driving mid-size and large panel displays containing up to ten white LEDs in series.
LED dimming can be done by using a DC voltage, a logic signal, or a pulse width modulation (PWM) signal. The shutdown input pin allows the device to be placed in power-down mode with 'zero' quiescent current.
In addition to thermal protection and overload current limiting, the device also enters a very low power operating mode during 'Open LED' fault conditions.
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Features |
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Switch Current Limit 750 mA
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Drives High Voltage LED strings (38 V)
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Low Quiescent Ground Current 0.6 mA
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1 MHz Fixed Frequency Low noise Operation
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Soft start “in-rush” current limiting
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Shutdown current less than 1 µA
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Open LED Overvoltage Protection
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Automatic Shutdown at 1.9 V (UVLO)
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Thermal overload protection
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Applications |
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End Products |
- LED Drive for Portable Electronics
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- GPS Navigation Systems
- Portable Media Players
- Digital Still Cameras
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