RICOH RN5T652 User Guide
Summary
This integrated circuit is a dedicated power management solution designed specifically to regulate and provide robust power supply for white LED lighting systems. The manual provides comprehensive development specifications covering the device's functional blocks, including LDO regulators, thermal shutdown protection, and efficient charge pump operation. It details the I²C communication interface and includes detailed application circuits and flowcharts, making it an essential resource for engineers designing reliable, optimized LED power applications.
Page 1 Text Content
Charge-Pump for White LED and Power Supply
RN5T652 Development Specifications
Rev. 1.5
RICOH COMPANY, LTD. Electronic Devices Company
This specification is subject to change without notice.
Page Summary Contents For RICOH RN5T652 User Guide
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Charge-Pump for White LED and Power Supply RN5T652 Development Specifications Rev. 1.5 RICOH COMPANY, LTD. Electronic Devices Company This specification is subject to change without notice.
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RN5T652 Rev.1.5 Table of Contents 1. Outline 2. Feature 3. Pin Configuration 4. Block Diagram..............................................................................................................
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RN5T652 Rev.1.5 7.3 LDO1 / LDO2 Output Voltage............................................................................................................... 7.4 Others Function 8. Electrical Characte...
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RN5T652 Rev. 1.5 1. Outline RN5T652 contains constant frequency charge pump to optimize for white LED application and two low-noise LDOs. Output enable/disable, LEDs current setting and LDO output vol...
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RN5T652 Rev. 1.5 3. Pin Configuration (TOP VIEW) DIN3 LDOUT1 DIN2 VIN3 DIN1 LDOUT2 VOUT RN5T652 N.C. C1P N.C. C2P N.C. C2M N.C. IN IN IN IN 1M QFN0404-28 pin Pin No. Name Pin No. Name Pin No. Name Pin...
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RN5T652 Rev. 1.5 4. Block Diagram C2M LDO1 C1P LDOUT1 Charge Pump LDOUT2 VOUT GND2 2.2u F PGND1 Thermal Shutdown DIN1 SCL @25m A Digital STBB CC Driver (Main) @25m A DIN4 5bit DAC @25m A DIN5 CC Drive...
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RN5T652 Rev. 1.5 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 driver current control output 1 4...
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RN5T652 Rev. 1.5 6. Functional Blocks 6.1 Regulators 6.1.1 LDO1 Electrical Characteristics Operating Conditions (Unless otherwise specified) VBATT = 3.6V, CREFO = 1μF, Ta = 25℃ Symbol Parameter Condit...
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RN5T652 Rev. 1.5 6.1.2 LDO2 Electrical Characteristics Operating Conditions (Unless otherwise specified) VBATT = 3.6V, CREFO = 1μF, Ta = 25℃ Symbol Parameter Condition Min Typ Max Units 50μA＜IOUT2＜300...
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RN5T652 Rev. 1.5 6.2 Thermal Shutdown Circuit The thermal shutdown circuit is consisted of two temperature detection circuits and an op-amp. 6.2.1 Thermal Shutdown Block Diagram Temperature Temperatur...
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RN5T652 Rev. 1.5 6.3 Charge Pump RN5T652 charge pump drives up to six white LEDs and one strobe with regulated constant current for uniform intensity. 6.3.1 Block Diagram C2MC1M C2PC1P Charge Pump PGN...
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RN5T652 Rev. 1.5 6.3.2 Operation Initial and 1x mode When any channel is turned ON, charge pump output (VOUT) voltage becomes VIN1 voltage. In this time, Soft-start prevents the inrush current. As a r...
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RN5T652 Rev. 1.5 6.3.3 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 fails as an open cir...
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RN5T652 Rev. 1.5 6.3.6 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 Units Charge Pump Operating Voltage ...
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RN5T652 Rev. 1.5 6.3.7 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 driven by the current set in the st...
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RN5T652 Rev. 1.5 6.5 CPU Interface RN5T652 uses I2C-Bus system for CPU connection through 2-wires. Connection and transfer system of I2C-Bus are described in the following sections. 6.5.1 Start and St...
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RN5T652 Rev. 1.5 6.5.2 Data Transmission and its Acknowledge After start condition, data is transmitted by 1byte (8bits). The number of bytes that can be transmitted per transmission is not limited. R...
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RN5T652 Rev. 1.5 6.5.4 Data Transmission Write Format The transmission format for the slave address allocated to each IC is defined by I2C-Bus standard. However transmission method of address informat...
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RN5T652 Rev. 1.5 6.5.6 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 connected to these two lines are desi...
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RN5T652 Rev. 1.5 6.5.7 AC Characteristics of I2C-Bus Operating Conditions (Unless otherwise specified) VBATT = 3.6V, CREFO = 1μF, Ta = 25℃ Symbol Parameter Condition Min Typ Max Units f SCL SCL Clock ...
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RN5T652 Rev. 1.5 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 Initial value 0 0 0 0 0 Sub Lumina...
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RN5T652 Rev. 1.5 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 Flash Strobe D4 D3 D2 D1 D0 off off...
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RN5T652 Rev. 1.5 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 individually set by D4 bit. LDO Voltage (V...
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RN5T652 Rev. 1.5 8. Electrical Characteristics 8.1 Absolute Maximum Ratings The operation exceeding “Absolute Maximum Ratings” below may cause permanent damage to the device. The operation of the devi...
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RN5T652 Rev. 1.5 8.4 DC Characteristics Digital Part Input (Input pin) SCL, SDA, STBB Operating Conditions (Unless otherwise specified) VBATT = 3.6V, CREFO = 1μF, Ta = 25℃ Symbol Parameter Condition M...
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RN5T652 Rev. 1.5 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 DIN6 to GND. Fig 9-2 Mono 5 LEDs ©2...
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RN5T652 Rev. 1.5 (3) Dual Main 3 LEDs and Sub 2 LEDs Control flow chart VIN1 VOUT Start C1P 2.2μF Main LED Sub LED Flash PGND1 GPIO1 ⇒ “H” 4.7u F C1M (RN5T652 Enable) C2P Li-ion Battery 1μF Transmissi...
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RN5T652 Rev. 1.5 10. Package Information ©2009 Rev. 1.5 Page 27
Manual Details
| Brand | Ricoh |
|---|---|
| Pages | 28 |
| File Size | 2.29 MB |
| Published | June 01, 2026 |
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Frequently Asked Questions
What is the typical input leakage current?
The input leakage current (IL) is specified as V=0～VEN -3 μA.
How is the device sleep state activated?
Setting GPIO1 to a 'Low' voltage ('L') puts the board into Sleep mode, turning off Main/Sub LEDs and preventing further transmission.
What are the recommended decoupling capacitor values for general use?
For some applications, 2.2μF capacitors (C1P) are used in conjunction with various resistors or filters.
Does this device support external debugging or diagnostics?
The manual details an I²C-Bus connection using SDA and SCL lines for communication with the CPU interface.