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Charge pump for White LED RN5T649 Development Specifications Rev. 1.2 RICOH COMPANY, LTD. Electronic Devices Company This specification is subject to change without notice.
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RN5T649 CHARGE PUMP FOR WHITE LED Table of Contents 1. Outline.............................................................................................................................................
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CHARGE PUMP FOR WHITE LED RN5T649 1. Outline RN5T649 contains a constant frequency charge pump, which is optimized for White LED application. Output enable/disable, LEDs current and LDOs ON/OFF are in...
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CHARGE PUMP FOR WHITE LED RN5T649 4. Pin Configuration 2P LD LEDCTL DIN3 1M IN C2M DIN4 C3P TOP VIEW LDOUT2 VOUT VCCCOM C1P LDOUT1 Fig 4-1 Pin Configuration ©2009 Rev. 1.2 Page 4
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CHARGE PUMP FOR WHITE LED RN5T649 5. Typical Application Circuit VCCCP Charge Pump GNDCP GND Feed Back Thermal Shutdown Adjust Voltage Controlled with LDOCTL GPIO of CPU Logic VCCCOM LDO1LDOUT1 Curren...
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RN5T649 CHARGE PUMP FOR WHITE LED 6. Pin Description No. Name I/O Description Notes 1 LEDCTL I ON/OFF control and Current setting of LED driver 2 C2M - Charge pump boost capacitor connection 3 C3P - C...
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CHARGE PUMP FOR WHITE LED RN5T649 7. Functional Blocks 7.1 Single Wire Serial Pulse I/F of LDO1/2 RN5T649 has 2 Low Drop Output regulators, LDO1 and LDO2. At time of shipment, the output voltage can b...
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RN5T649 CHARGE PUMP FOR WHITE LED 7.2 LDO1/2 Electrical Characteristics Unless otherwise specified, VCCCOM=3.6V, Ta=25℃, Cout=1.0u F Symbol Parameter Condition Min Typ Max Units Output Voltage LDOUT*1...
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CHARGE PUMP FOR WHITE LED RN5T649 7.3 Charge Pump RN5T649 drives up to 4 white LEDs with regulated constant current. Utilizing 1x/1.33x/1.5x charge pump modes achieves high-efficiency. On/off of LED i...
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CHARGE PUMP FOR WHITE LED RN5T649 7.3.2 Backlight LED For maximized power efficiency, Charge pump operates 1x mode, 1.33x mode and 1.5x mode, where the operation mode is determined by comparing the fo...
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CHARGE PUMP FOR WHITE LED RN5T649 7.3.3 Protection Circuit When any DIN_ pin is floating or grounded, VOUT voltage is limited below protection voltage by gating on/off charge pump. In case any LED fai...
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CHARGE PUMP FOR WHITE LED RN5T649 7.3.6 Luminance Control RN5T649 charge pump drives 4 LEDs with regulated constant current for uniformed intensity. LEDCTL input enables/disables LED and adjusts curre...
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CHARGE PUMP FOR WHITE LED RN5T649 7.3.7 Single Wire Serial Pulse I/F of LED Driver When LEDCTL goes high, LEDs are enabled at full luminance. After, the subsequent low going pulse reduces LED current ...
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RN5T649 CHARGE PUMP FOR WHITE LED 7.3.8 Charge Pump Electrical Characteristics Unless otherwise specified, VCCCP=3.6V, VCCCOM=3.6V, Ta=25℃, C1=C2=C3=1u F, Cout=2.2u F Symbol Parameter Condition Min Ty...
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RN5T649 CHARGE PUMP FOR WHITE LED 7.4 UVLO (Under Voltage Lock Out) Unless otherwise specified, Ta=25℃ Symbol Parameter Condition Min Typ Max Units VRelease Under voltage lock out threshold VCCVIN ris...
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RN5T649 CHARGE PUMP FOR WHITE LED 7.5 Thermal Shutdown Circuit Overheat state can be detected by comparing the output voltages from two temperature detection circuits, which have different temperature...
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RN5T649 CHARGE PUMP FOR WHITE LED 8. Electrical Characteristics 8.1 Absolute Maximum Ratings Symbol Parameter Condition Rated value Units VCC_abs Power Supply Voltage Battery Voltage Input Pins -0.3～6...
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CHARGE PUMP FOR WHITE LED RN5T649 9. Package Information ©2009 Rev. 1.2 Page 18
