Free electronic circuit design and schematic diagram
Resistor and LM317L act as a current regulator set to 40 ma. Current will flow from the battery through one pair of LEDs, and then to the regulator, through the other pair of LEDs and finally back to the battery. Noise on the power supply lines filtered out by the capacitor. To make the current through them is roughly equivalent, […]
Read moreLow efficiency and heat generation are the two biggest shortcomings of using linear regulators versus switching regulators for applications with high input/output voltage difference. These two things is used to prevent the usage of linear devices in many applications, specially in those with low power consumption requirements. However, the option of using linear LED drivers to address backlighting applications does […]
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This is Resonant Mode LED Driver circuit. This circuit is used to give a constant DC current through a string of a given number of LEDs. This circuit uses flyback, boost, or buck topology. Each of them has disadvantages and advantages depending on the number of LEDs being driven in series, the LED output current, if dimming is required, if […]
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A circuit that can drive three to four high power LEDs is shown on figure below. The ADP 1610 is an adjustable boost regulator. The voltage headroom and current for the LEDs is provided by this device. An average gain of 12 feedback network that servos the Rset voltage and the ADP1610 FB pin 1.2 V band gap reference voltage […]
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The MAX931 series has capability to produce high output source which is useful for driving LEDs. The circuit below shows an example of simple four-stage level detector. Vin=(R1R2)/R1 volts gives the full-scale threshold (all LEDs on). The other thresholds are at 1/4 full scale, 1/2 full scale, and 3/4 full scale. The current into the LEDs is limited by the […]
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We can use SSL3250A (an asynchronous boost photo flash dual LED driver) for mobile application. This device ensure a lot of implementation possibilities because it has wide input voltage range and the large maximum output current at a wide output voltage range. It has long battery life and low power strain because of it’s high efficiency and soft-start. This device […]
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The TPS61160/1 is a boost converter that drives up to 10 LEDs in series with a 40-V rated integrated switch FET. To reduce output ripple, improve convertion efficiency, and allows for the use of small external component, the boost converter is very usefull. The default white LED current is set with the external sensor resistor Rset, and the feedback voltage […]
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