RICOH RN5T653 User Guide
Summary
The RN5T653 is a constant frequency charge pump specifically designed and optimized for high-efficiency White LED backlights. This manual serves as a comprehensive technical guide for engineers, detailing its electrical specifications, functional blocks (including regulators, luminance control, and PWM adjustment), and operational parameters. Users will find detailed information on absolute maximum ratings, recommended operating conditions, power consumption management, and internal protection circuits like thermal shut-down mechanisms, ensuring optimal integration into illumination systems.
Page 1 Text Content
Charge pump for White LED
RN5T653 Development Specifications
Rev. 1.8
RICOH COMPANY, LTD. Electronic Devices Company
This specification is subject to change without notice.
Page Summary Contents For RICOH RN5T653 User Guide
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Charge pump for White LED RN5T653 Development Specifications Rev. 1.8 RICOH COMPANY, LTD. Electronic Devices Company This specification is subject to change without notice.
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RN5T653 CHARGE PUMP FOR WHITE LED Table of Contents 1. Outline.............................................................................................................................................
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RN5T653 CHARGE PUMP FOR WHITE LED 1. Outline RN5T653 contains a constant frequency charge pump, which is optimized for White LED application. Output enable/disable, LEDs current and LDOs output voltag...
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RN5T653 CHARGE PUMP FOR WHITE LED 4. Pin Configuration DIN2 VCCVIN2 DIN3 LDOUT2 DIN4 TOP VIEW LEDCTL 1P IN C2P LDO2CTL VOUT LDO1CTL 2M EF LD T1 Fig 4-1 Pin Configuration ©2009 Rev. 1.8 Page 3
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RN5T653 CHARGE PUMP FOR WHITE LED 5. Typical Application Circuit VCCVIN1 VCCVIN2 VREFVREF 1.0u F GND LDO1LDOUT1 Charge Pump LDOUT2 LDO2 GND2 2.2u F LDO1CTL PGND1 Digital LDO2CTL LEDCTL DIN1 @20m A The...
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RN5T653 CHARGE PUMP FOR WHITE LED 6. Pin Description No. Name I/O Description Notes 1 DIN2 O LED driver current control output 2 DIN3 O LED driver current control output 3 DIN4 O LED driver current co...
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RN5T653 CHARGE PUMP FOR WHITE LED 7. Functional Blocks 7.1 Regulators RN5T653 has 2 Low Drop Output regulators, LDO1 and LDO2. (See Table 6-1) On/Off operation of each LDO are controllable with LDO1/2...
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RN5T653 CHARGE PUMP FOR WHITE LED 7.2 LDO1/2 Electrical Characteristics Unless otherwise specified, VCCVIN=3.6V, Ta=25℃, Cout=1.0u F Symbol Parameter Condition Min Typ Max Units 50u A＜IOUT＜150m A VOUT...
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RN5T653 CHARGE PUMP FOR WHITE LED 7.3 Charge Pump RN5T653 drives up to 4 white LEDs with regulated constant current. Utilizing 1x/1.5x charge pump modes achieves high-efficiency. On/off of LED is indi...
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RN5T653 CHARGE PUMP FOR WHITE LED 7.3.2 Backlight LED For maximized power efficiency, the charge pump operates 1x mode and 1.5x mode, where the operation mode is determined by comparing the forward vo...
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RN5T653 CHARGE PUMP FOR WHITE LED 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 that any LE...
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RN5T653 CHARGE PUMP FOR WHITE LED 7.3.6 Luminance Control RN5T653 charge pump drives 4 LEDs with regulated constant current for uniformed intensity. LEDCTL input is used to enable, disable and adjust ...
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RN5T653 CHARGE PUMP FOR WHITE LED 7.3.7 PWM Adjustment with Time Control When LEDCTL goes high, LEDs are enabled at the maximum luminance. After subsequent low going pulse reduces LED current in logar...
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RN5T653 CHARGE PUMP FOR WHITE LED 7.3.7.3 Operation Flow Case1: 1. Power ON Power ON : LEDCTL pin turns to "H" 2. Luminance Setting Luminance Setting ex) 16.8m A (4 Pulses) 3.Wait Subroutine...
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RN5T653 CHARGE PUMP FOR WHITE LED Case2: 1.Power ON Power ON : LEDCTL pin turn to "H" 2.Luminance Setting Luminance Setting ex)16.8m A (4 Pulses) LEDCTL pin is maintained at "H" du...
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RN5T653 CHARGE PUMP FOR WHITE LED Case3: 1.Power ON Power ON : LEDCTL pin turns to "H" 2.Luminance Setting Luminance Setting Value:16.8m A(4 Pulses) IRQ is generated Luminance Setting Value:...
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RN5T653 CHARGE PUMP FOR WHITE LED 7.3.8 Charge Pump Electrical Characteristics Operating Conditions (unless otherwise specified) VCCVIN=3.6V, Ta=25℃, C1=C2=1u F, Cout=2.2u F Symbol Parameter Condition...
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RN5T653 CHARGE PUMP FOR WHITE LED 7.5 Thermal Shut-down Circuit Overheat state can be detected by comparing the output voltages from two temperature detection circuits, which have different temperatur...
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RN5T653 CHARGE PUMP FOR WHITE LED 8. Electrical Characteristics 8.1 Absolute Maximum Ratings Symbol Parameter Condition Rated value Units VCCVIN Power Supply Voltage Battery Voltage Input Pins -0.3～6....
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RN5T653 CHARGE PUMP FOR WHITE LED 9. Package Information ©2009 Rev. 1.8 Page 19
Manual Details
| Brand | Ricoh |
|---|---|
| Pages | 20 |
| File Size | 1.27 MB |
| Published | May 27, 2026 |
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Frequently Asked Questions
What prevents damage if this device overheats?
The Thermal Shut-down circuit monitors output voltages and will automatically turn off to protect itself from overheating.
Does the chip offer brightness or power adjustment options?
Yes, it supports Luminance Control and PWM Adjustment with Time Control for fine-tuning.
What is the recommended operating voltage range (VCC_VIN)?
The recommended VCC_VIN operating voltage window is typically 2.7V to 4.5V.
What is the allowed temperature range for storage?
For storage, the absolute maximum temperature range is specified from -55°C to +125°C.