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RT4812 Dataheets PDF



Part Number RT4812
Manufacturers Richtek Technology
Logo Richtek Technology
Description High Efficiency Boost Converter
Datasheet RT4812 DatasheetRT4812 Datasheet (PDF)

RT4812 High Efficiency Boost Converter General Description The RT4812 allows systems to take advantage of new battery chemistries that can supply significant energy when the battery voltage is lower than the required voltage for system power ICs. By combining built-in power transistors, synchronous rectification, and low supply current; this IC provides a compact solution for systems using advanced Li-Ion battery chemistries. The RT4812 is a boost regulator designed to provide a minimum output.

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RT4812 High Efficiency Boost Converter General Description The RT4812 allows systems to take advantage of new battery chemistries that can supply significant energy when the battery voltage is lower than the required voltage for system power ICs. By combining built-in power transistors, synchronous rectification, and low supply current; this IC provides a compact solution for systems using advanced Li-Ion battery chemistries. The RT4812 is a boost regulator designed to provide a minimum output voltage from a single-cell Li-Ion battery, even when the battery voltage is below system minimum. In boost mode, output voltage regulation is guaranteed to a maximum load current of 2.1A. Quiescent current in Shutdown Mode is less than 1A, which maximizes battery life. Ordering Information RT4812 Package Type J8F : TSOT-23-8 (FC) Lead Plating System G : Green (Halogen Free and Pb Free) Note : Richtek products are :  RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.  Suitable for use in SnPb or Pb-free soldering processes. Features  CMCOT Topology and Small Output Ripple when VIN close VOUT Voltage  Operates from a Single Li-ion Cell : 1.8V to 5.5V  Adjustable Output Voltage : 1.8V to 5.5V  PSM Operation  Up to 96% Efficiency  Boost Current Limit  Output Over-Voltage Protection  Pin Adjustable Average Output Current Limit Threshold (2 Levels)  Internal Compensation  Output Discharge  Output Short Protection  True Load Disconnect Applications  Single-Cell Li-Ion, LiFePO4 Smart-Phones  Portable Equipment Marking Information 0L=DNN 0L= : Product Code DNN : Date Code Simplified Application Circuit RT4812 L1 VIN SW VOUT VOUT C1 R1 C3 VIN C2 FB R2 EN R3 H/L ILIM GND Copyright © 2022 Richtek Technology Corporation. All rights reserved. DS4812-09 March 2022 is a registered trademark of Richtek Technology Corporation. www.richtek.com 1 RT4812 Pin Configuration ILIM EN SW GND (TOP VIEW) 87 6 5 2 34 VIN FB VOUT PGND TSOT-23-8 (FC) Functional Pin Description Pin No. Pin Name Pin Function 1 VIN Power input. Input capacitor CIN must be placed as close to IC as possible. 2 FB Voltage feedback. 3 VOUT Boost converter output. 4 PGND Power ground. 5 GND Analog ground. 6 SW Switching node. 7 EN Enable input (1 enabled, 0 disabled), must not be floating. 8 ILIM Average output current limit control pin. (H/L) Functional Block Diagram VOUT VIN SW Control Gate ILIM OCP DRV SW EN PGND Digital CTRL PWM CTRL OSC OTP UVLO AMP + VREF FB GND Copyright © 2022 Richtek Technology Corporation. All rights reserved. www.richtek.com 2 is a registered trademark of Richtek Technology Corporation. DS4812-09 March 2022 Operation The RT4812 combined built-in power transistors, synchronous rectification, and low supply current, it provides a compact solution for system using advanced Li-Ion battery chemistries. In boost mode, output voltage regulation is guaranteed to a maximum load current of 2.1A. Quiescent current in Shutdown mode is less than 1A, which maximizes battery life. Mode LIN 1 LIN LIN 2 Soft-Start Boost Depiction Linear startup 1 Linear startup 2 Boost soft-start Boost mode Condition VIN > VOUT VIN > VOUT VOUT < VOUT(MIN) VOUT = VOUT(MIN) LIN State When VIN is rising, it enters the LIN State. There are two parts for the LIN state. It provides maximum current for 1A to charge the COUT in LIN1, and the other one is for 3A in LIN2. By the way, the EN is pulled high and VIN > UVLO. As the figure shown, if the timeout is over the specification, it will enter the Fault mode. EN = 1, Vin > UVLO LIN 1 Timeout < 512μs Timeout > 512μs Soft-Start LIN 2 Timeout < 1024μs Timeout > 1024μs Boost mode Fault State Figure 1. RT4812 State Chart RT4812 Startup and Shutdown State When VIN is rising and through the LIN state, it will enter the Startup state. If EN is pulled low, any function is turned-off in shutdown mode. Soft-Start State It starts to switch in Soft-start state. After the LIN state, output voltage is rising with the internal reference voltage. Fault State As the Figure 1 shown, it will enter to the Fault state as below,  The timeout of LIN2 is over the 1024s. It will be the high impedance between the input and output when the fault is triggered. A restart will be start after 20ms. OCP The converter senses the current signal when the high-side P-MOSFET turns on. As a result, the OCP is cycle-by-cycle current limitation. If the OCP occurs, the converter holds off the next on pulse until inductor current drops below the OCP limit. OTP The converter has an over-temperature protection. When the junction temperature is higher than the thermal shutdown rising threshold, the system will be latched and the output voltage will no longer be regulated until the junction temperature drops under the falling threshold. Input Voltage POR (Power-On Reset) The RT4812 is implemente.


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