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The Problem and The Solution
LCD display modules require a backlight unit (BLU) to supply the light illuminating the screen. However, the LCD module can use as much as 50% of the active power consumed by a mobile handset. As the usage model for mobile devices shifts toward increased use of multimedia content, the display is on for progressively longer periods of time. With the high amounts of power consumed by the display module, this can result in significantly shortened battery life, compromising the user experience.
Historically, LED drivers have been functionally independent of LCD display drivers. However, as power savings becomes an increasingly significant factor in display module performance, communication between LED and LCD drivers is an essential requirement. Our new family of LED drivers, combined with Leadis?own proprietary algorithm embedded in our PowerLite?family of LCD drivers, provides a complete system solution for display modules achieving up to 50% power savings compared to standard architectures
LED Driver Products
Leadis offers high-efficiency charge-pump based LED driver products targeted at mobile backlighting applications.
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The LDS8841 is a high-efficiency 1x/1.5x fractional charge pump capable of driving up to four LEDs at 31mA each. LED dimming control is programmable with a one wire interface stepping down current levels on all four channels in 1mA steps, supporting levels from 0mA to 31mA.
Input voltages from 3v to 5.5v are supported with efficiency up to 91%. Operation at a constant switching frequency of 1MHz enables low noise input ripple and utilization of small external ceramic capacitors. Other product features include soft start and current limiting, thermal shutdown and short circuit protection, and a 뱙ero?current shutdown mode. The LDS8841 is offered in a 12-lead thin DFN 3mm x 3mm package with a maximum height of 0.8mm. |
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The LDS8862 is a high-efficiency 1x/1.5x fractional charge pump capable of driving up to six LEDs at 32mA each. LED dimming control is programmable with an I2C interface enabling current level adjustment on all six channels in 0.5mA steps, supporting levels from 0mA to 32mA.
Input voltages from 3v to 5.5v are supported with efficiency up to 91%. Operation at a constant switching frequency of 1MHz enables low noise input ripple and utilization of small external ceramic capacitors. Other product features include soft start and current limiting, thermal shutdown and short circuit protection, and a 뱙ero?current shutdown mode. The LDS8862 is offered in a 16-lead thin QFN 4mm x 4mm package with a maximum height of 0.8mm. |
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The LDS8830 is a high-efficiency 1x/1.33x/1.5x/2x fractional charge pump capable of driving up to three LEDs at up to 32mA each. LED dimming control is programmable with a one-wire interface enabling current level adjustment from 1mA to 32mA. LED channel matching is supported within +/-1.5%, with current accuracy at +/-2%. Input voltages from 2.5v to 5.5v are supported with efficiency up to 92%. Operation at switching frequencies of 1.3MHz (1.5x mode) and 1MkHz (1.33x and 2x modes) enables low noise input ripple and utilization of small external ceramic capacitors. Other product features include soft start and current limiting, thermal shutdown and short circuit protection, and a low current shutdown mode of 1uA max. The LDS8830 is offered in a tiny 12-lead XQFN 2.5mm x 2.5mm with max height of 0.4mm or in a 16-lead TQFN or 12-lead TDFN 3mm x 3mm package with a max height of 0.8mm. |
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The LDS8842 is a high-efficiency 1x/1.33x/1.5x/2x fractional charge pump capable of driving up to four LEDs at up to 25mA each. LED dimming control is programmable with a one-wire interface enabling current level adjustment from 0.78mA to 25mA. LED channel matching is supported within +/-1.5%, with current accuracy at +/-2%. Input voltages from 2.5v to 5.5v are supported with efficiency up to 92%. Operation at switching frequencies of 1.3MHz (1.5x mode) and 1MHz (1.33x and 2x modes) enables low noise input ripple and utilization of small external ceramic capacitors. Other product features include soft start and current limiting, thermal shutdown and short circuit protection, and a low current shutdown mode of 1uA max. The LDS8842 is offered in a 16-lead thin QFN 3mm x 3mm package with a maximum height of 0.8mm. |
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The LDS8861 is a high-efficiency 1x/1.33x/1.5x/2x fractional charge pump capable of driving up to six LEDs at up to 32mA each. LED dimming control is programmable with a one-wire interface enabling current level adjustment from 0.25mA to 32mA. LED channel matching is supported within +/-1%, with current accuracy at +/-3%. Input voltages from 2.3v to 5.5v are supported with efficiency up to 92%. Operation at switching frequencies of 1.1MHz (1.5x mode) and 800kHz (1.33x and 2x modes) enables low noise input ripple and utilization of small external ceramic capacitors. Other product features include soft start and current limiting, thermal shutdown and short circuit protection, and a low current shutdown mode of 1uA max. The LDS8861 is offered in a 16-lead thin QFN 3mm x 3mm package with a maximum height of 0.8mm. |
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The LDS8864 is a multi-mode fractional charge pump with low dropout voltage that can drive up to six LEDs with efficiency up to 90%. The PWM1/PWM2 logic inputs function as a chip enable and a PWM mode LED brightness control. The maximum LED current is factory preset and can be programmed in the range from 0.5mA to 32mA in 0.5mA steps. The multi-fractional charge pump supports a wide range of input voltages from 2.7V to 5.5V. The device is available in a 16-lead TQFN 3mm x 3mm package with a maximum height of 0.8mm. |
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The LDS8865 is a high-efficiency multi-mode fractional charge pump with ultra low dropout voltage that can drive up to six LEDs. Inclusion of an ultra low dropout PowerLite Current Regulator increases the efficiency up to 93%. The PWM1/PWM2 logic inputs function as a chip enable and a PWM mode LED brightness control. The maximum LED current is factory preset and can be programmed in the range from 0.5mA to 32mA in 0.5mA steps. The multi-fractional charge pump supports a wide range of input voltages from 2.7V to 5.5V. The device is available in a 16-lead TQFN 3mm x 3mm package with a maximum height of 0.8mm. |
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The LDS8866 is a high-efficiency multi-mode fractional charge pump with ultra low dropout voltage that can drive up to six LEDs. Inclusion of a 1.33x fractional charge pump mode and ultra low dropout PowerLite Current Regulator increases the efficiency up to 95%. The 1.33x mode requires no additional external capacitors. The PWM1/PWM2 logic inputs function as a chip enable and a PWM mode LED brightness control. The maximum LED current is factory preset and can be programmed in the range from 0.5mA to 32mA in 0.5mA steps. The multi-fractional charge pump supports a wide range of input voltages from 2.7V to 5.5V. The device is available in a 16-lead TQFN 3mm x 3mm package with a maximum height of 0.8mm. |
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