RICOH RN5T651 Owner's Manual & User Guide
Summary
This comprehensive development manual details the RN5T651, a specialized charge-pump circuit designed for efficient power management in white LED lighting arrays. It provides engineers with full technical specifications, covering advanced regulated power features such as dual LDOs, step-down DC/DC converters, thermal shutdown protection, and I2C communication protocols. This resource is essential for developers integrating reliable and highly controlled power delivery solutions into professional illumination systems.
Page 1 Text Content
Charge-Pump for White LED and Power Supply
RN5T651 Development Specifications
Rev. 3.4
RICOH COMPANY, LTD. Electronic Devices Company
This specification is subject to change without notice.
Page Summary Contents For RICOH RN5T651 Owner's Manual & User Guide
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Charge-Pump for White LED and Power Supply RN5T651 Development Specifications Rev. 3.4 RICOH COMPANY, LTD. Electronic Devices Company This specification is subject to change without notice.
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RN5T651 Charge-Pump for White LED and Power Supply Table of Contents 1. Outline............................................................................................................................
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RN5T651 Charge-Pump for White LED and Power Supply 6.6.4 Data Transmission Write Format 6.6.5 Internal Register Write-in Timing............................................................................
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RN5T651 Charge-Pump for White LED and Power Supply 1. Outline RN5T651 contains constant frequency charge pump to optimize for white LED application, step-down DC/DC converter and two low-noise LDOs. O...
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RN5T651 Charge-Pump for White LED and Power Supply 3. Pin Configuration (TOP VIEW) DIN3 LDOUT1 DIN2 VIN3 DIN1 LDOUT2 VOUT RN5T651 FB C1P PGND2 C2P LX IN C2M VIN2 IN IN 1M QFN0404-28 pin Pin No. Name P...
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RN5T651 Charge-Pump for White LED and Power Supply 4. Block Diagram VIN1 C2P 4.7u F 1u F LX C1P Charge Pump 2.2u H DC/DC C1M Step-down FB VOUT PGND1 PGND2 Thermal Shutdown DIN1 @25m A VREF DIN2 GND GN...
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RN5T651 Charge-Pump for White LED and Power Supply 5. Pin Description No. Name I/O Function Notes 1 DIN3 O LED driver current control output 3 2 DIN2 O LED driver current control output 2 3 DIN1 O LED...
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RN5T651 Charge-Pump for White LED and Power Supply 6. Functional Blocks 6.1 Regulators 6.1.1 LDO1 Electrical Characteristics Operating Conditions (unless otherwise specified) VBATT = 3.6V, CREFO = 1μF...
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RN5T651 Charge-Pump for White LED and Power Supply 6.1.2 LDO2 Electrical Characteristics Operating Conditions (unless otherwise specified) VBATT = 3.6V, CREFO = 1μF, Ta = 25℃ Symbol Item Condition Min...
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RN5T651 Charge-Pump for White LED and Power Supply 6.2 Step-down DC/DC Converters (a) Output voltage The output voltage is decided according to the resistance ratio of external resistor. Please refer ...
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RN5T651 Charge-Pump for White LED and Power Supply 6.2.3 Step-down DC/DC Convertors Electrical Characteristics Operating Conditions (unless otherwise specified) VBATT = 3.6V, CREFO = 1μF, Ta = 25℃ Sym...
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RN5T651 Charge-Pump for White LED and Power Supply 6.3 Thermal Shutdown Circuit The thermal shutdown circuit is consisted of two temperature detection circuits and an op-amp. 6.3.1 Thermal Shutdown Bl...
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RN5T651 Charge-Pump for White LED and Power Supply 6.4 Charge Pump RN5T651 charge pump drives up to six white LEDs and one strobe with regulated constant current for uniform intensity. 6.4.1 Block Dia...
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RN5T651 Charge-Pump for White LED and Power Supply 6.4.2 Operation Initial and 1x mode When any channel is turned ON, charge pump output (VOUT) voltage becomes VIN1 voltage. In this time, Soft-start p...
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RN5T651 Charge-Pump for White LED and Power Supply 6.4.3 Protection circuit When any DIN_ pin is floating or grounded, VOUT voltage is limited below protection voltage by gating on/off charge pump. In...
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RN5T651 Charge-Pump for White LED and Power Supply 6.4.6 Charge Pump Electrical Characteristics Unless otherwise specified, VIN=3.6V, Ta=25℃, C1=C2=1u F, Cout=2.2u F Parameter Conditions Min Typ Max U...
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RN5T651 Charge-Pump for White LED and Power Supply 6.4.7 STBB Logic Input STBB input is used to control the flash LEDs without accessing I2C. When STBB is driven to "L", the flash LEDs are d...
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RN5T651 Charge-Pump for White LED and Power Supply 6.6 CPU Interface RN5T651 uses I2C -Bus system for CPU connection through 2-wires. Connection and transfer system of I2C -Bus are described in the fo...
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RN5T651 Charge-Pump for White LED and Power Supply 6.6.2 Data Transmission and its Acknowledge After start condition, data is transmitted by 1byte (8bits). The number of bytes that can be transmitted ...
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RN5T651 Charge-Pump for White LED and Power Supply 6.6.4 Data Transmission Write Format The transmission format for the slave address allocated to each IC is defined by I2C-Bus standard. However trans...
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RN5T651 Charge-Pump for White LED and Power Supply 6.6.6 Connection of I2C-Bus 2 wires of SCL and SDA are connected to I2C-Bus and used for transmitting clock pulses and data individually. All ICs con...
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RN5T651 Charge-Pump for White LED and Power Supply 6.6.7 AC Characteristics of I2C-Bus Operating Conditions (unless otherwise specified) VBATT = 3.6V, CREFO = 1μF, Ta = 25℃ Symbol Item Condition Min T...
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RN5T651 Charge-Pump for White LED and Power Supply 7. Register 7.1 Register Map SDA Control Byte COMMAND DATA Function C2 C1 C0 D4 D3 D2 D1 D0 Main Luminance 31-steps 25m A / LED max. 000 00000 = off ...
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RN5T651 Charge-Pump for White LED and Power Supply 7.2 Main / Sub / Flash / Strobe Luminance Each sink current of DIN1-4, 5, 6, and 7 can be set by the code of D4-D0. LED Current (m A) Data Main Sub F...
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RN5T651 Charge-Pump for White LED and Power Supply 7.3 LDO1 / LDO2 Output Voltage Each output voltage of LDO1 and LDO2 can be set by the code of D3-D0. And enable/disable of the output can be individu...
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RN5T651 Charge-Pump for White LED and Power Supply 7.5 Others Function Bit DATA Function 1 Enable D4 Main Enable 0 Disable 1 Enable D3 Sub Enable 0 Disable 1 Enable D2 DIN7 Enable 0 Disable 1 Enable D...
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RN5T651 Charge-Pump for White LED and Power Supply 8. Electrical Characteristics 8.1 Absolute Maximum Ratings The operation exceeding “Absolute Maximum Ratings”below may cause permanent damage to the ...
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RN5T651 Charge-Pump for White LED and Power Supply 8.4 DC Characteristics Digital part Input (Input Pin) SCL, SDA, STBB Operating Conditions (unless otherwise specified) VBATT = 3.6V, CREFO = 1μF, Ta ...
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RN5T651 Charge-Pump for White LED and Power Supply 9. Additional Application Circuit (1) Dual Main 4 LEDs and Sub 2 LEDs Fig 9-1 Dual Main 4 LEDs and Sub 2 LEDs (2) Mono 5 LEDs Note*: Please connect D...
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RN5T651 Charge-Pump for White LED and Power Supply (3) Dual Main 3 LEDs and Sub 2 LEDs Note*: Please connect DIN4 to GND. Fig 9-3 Dual Main 3 LEDs and Sub 2 LEDs (4)Mono 4 LEDs Note*: When DIN5 and 6 ...
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RN5T651 Charge-Pump for White LED and Power Supply 10. Package Information ©2009 Rev. 3.4 Page 30
Manual Details
| Brand | Ricoh |
|---|---|
| Pages | 31 |
| File Size | 2.82 MB |
| Published | May 29, 2026 |
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Frequently Asked Questions
What are the allowed ranges for the VIN power supply?
The minimum VIN voltage is 2.7V and the maximum is 4.5V. The VEN range is -1.8V to 4.2V.
Does this device include thermal protection?
Yes, it features a dedicated Thermal Shutdown Circuit that monitors temperature and shuts down operation if limits are exceeded.
What interface handles data communication?
It uses an I2C bus interface via the SCL, SDA, and STBB pins for communication.
What is the recommended operational temperature range?
The device can operate within a safe temperature range of -40°C to +85°C.