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Wide Input and Ultra-Low Quiescent Current Boost Converter with High Efficiency and I2C Flexible Control

EVB_RT4822WSC

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The RT4822 is a boost regulator designed to provide a minimum output voltage from a single-cell Li-Ion battery or two alkaline battery series, even when the battery voltage is below system minimum. Quiescent current in shutdown mode is less than 1µA, which maximizes battery life.

General Description

The RT4822 is a boost regulator designed to provide a minimum output voltage from a single-cell Li-Ion battery or two alkaline battery series, even when the battery voltage is below system minimum. Quiescent current in shutdown mode is less than 1µA, which maximizes battery life.



Performance Specification Summary

The boost conveter has an input voltage range from 1.8V to 5.5V, and the output voltage range is from 3.15V to 5.5V. It can operate in force bypass mode and boost mode. And the power-on inrush current and current limit are implemented serval setting for difference application. The RT4822 is available in a WL-CSP-9B 1.3x1.2 (BSC) package.


Table 1. RT4822WSC Evaluation Board Performance Specification Summary

Specification

Test Conditions

Min

Typ

Max

Unit

Input Voltage Range

1.8

--

5.5

V

Output Current

VIN > 3V, VOUT = 5V

0

--

1.5

A

Default Output Voltage

--

5

--

V

Operation Frequency

3

3.5

4

MHz

Output Ripple Voltage

VIN = 3.6V, VOUT = 5V, IOUT = 0.5A

--

40

--

mVp-p

Line Regulation

IOUT = 0.5A, VIN = 1.8V to 4.8V, VOUT = 5V

--

±1

--

%

Load Regulation

VIN = 3.6V, IOUT = 0.2A to 1A, VOUT = 5V

--

±1

--

%

Load Transient Response

VIN = 3.6V, VOUT = 5V ,IOUT = 50mA to 500mA

--

±3

--

%

Maximum Efficiency

VIN = 3.6V, VOUT = 5V, IOUT = 0.6A

--

93

--

%



Power-up Procedure

1. Connect input voltage (1.8V < VIN < 5.5V) to VIN pin.

2. Setting BOOST enable selection by CHIP_EN. (setting 0x05[0] by I2C)

3. Setting BOOST pre-charge current and BOOST_LIMIT for power on inrush current. (setting 0x00 by I2C)

4. To enable Boost converter by external EN pin or 0x05[5].

5. To connect an external load to output and verify the output voltage versus applied current.


Output Voltage Setting

The output voltage set by internal register in the following I2C table.

Addr

Reg Name

Bit

Bit Name

Default

Type

Description

0x02

BOOST_VOUT

7

Reserved

0

RW

Reserved

6:0

BOOST_VOUT

1101011

RW

Boost output voltage can be set voltage from 3.15V to 5.5V with 25mV/step.

0000000 to 0100001: 3.15V

1101011: 5V (default)

1111111: 5.5V



Detailed Description of Hardware

Headers Description and Placement

Technical Document Image Preview

Carefully inspect all the components used in the EVB according to the following Bill of Materials table, and then make sure all the components are undamaged and correctly installed. If there is any missing or damaged component, which may occur during transportation, please contact our distributors or e-mail us at evb_service@richtek.com.



Bill of Materials

Reference

Count

Part Number

Description

Package

Manufacture

CN1

1

CHEB254S006-CF1043

I2C

Cherng Weei

C1

1

EMK325BJ476KM-T

47µF/16V/X5R

1210

TAIYO YUDEN

C2

1

GRM155R60J475ME47

4.7µF/6.3V/X5R

0402

Murata

C4

1

0603X106M6R3CT

10µF/6.3V/X5R

0603

WALSIN

L1

1

DFE252012F-1R0M=P2

1.0µH/3.3A

2.5x2.0x1.2mm

Murata

R1, R2

2

WR06X2201FTL

22k/0603

0603

WALSIN

U1

1

RT4822WSC

Step-Up DC-DC Converter

WL-CSP-9B 1.3x1.2 (BSC)

RICHTEK



Typical Applications

EVB Schematic Diagram

Technical Document Image Preview

1. C1 is placed on input side, and the capacitors are design for long wire effect. If input source is close RT4822 then the capacitors are optional.

2. C4 is placed on output side, and the capacitor is optional for output voltage ripple improvement.


Measure Result

Output Ripple Measurement

Load Transient Response

Technical Document Image Preview

Technical Document Image Preview

Power On from EN

DVS up

Technical Document Image Preview

Technical Document Image Preview

Short Circuit Response

Sine Waveform Stability

Technical Document Image Preview

Technical Document Image Preview



Evaluation Board Layout

一張含有 文字, 電子用品, 螢幕擷取畫面 的圖片

自動產生的描述

Figure 1. Top View (1st layer)


Technical Document Image Preview

Figure 2. PCB Layout—Inner Side (2nd Layer)


Technical Document Image Preview

Figure 3. PCB Layout—Inner Side (3rd Layer)


一張含有 文字, 電子用品 的圖片

自動產生的描述

Figure 4. Bottom View (4th Layer)

Title Last Update Share Download
Evaluation Board User Guide 2023/02/17
Bill of Materials 2023/02/17
Schematic 2023/02/17
Gerber File 2023/02/17
RT4822
RT4822

The RT4822 integrates built-in power transistors, synchronous rectification, and low supply current to provide a compact solution for systems using advanced Li-Ion battery chemistries. The RT4822 is capable of supplying significant energy when the battery voltage is lower than the required voltage for system power ICs.

The RT4822 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 1500mA. Quiescent current in shutdown mode is less than 1μA, which maximizes the battery life. The regulator transitions smoothly between bypass and normal boost mode. The device can be forced into bypass mode to reduce quiescent current.

The RT4822 is available in the WL-CSP-9B 1.3x1.2 (BSC) package.

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