Renesas Rtka223021de0000bu High Voltage Buck Converter Evaluation Board Instruction Manual

RTKA223021DE0000BU High Voltage Buck Converter Evaluation Board
Instruction Manual

RTKA223021DE0000BU High Voltage Buck Converter Evaluation Board

The RAA223021 evaluation board (RTKA223021DE0000BU) is a high voltage buck converter that demonstrates a low-cost high performance non-isolated AC/DC conversion from a universal input of 85VAC to 265VAC, to a 12V output with the output current up to 667mA.
The board has built-in overcurrent, short-circuit, input brownout, and over-temperature protection, and is designed on a single-side PCB with a full-wave input rectification. It is pre-compliant with conducted EMI requirements by EN55022/CISPR 22.
RTKA223021DE0000BU uses the RAA223021 SOIC-7 packaged IC.

Features

• Universal input
• Single side PCB with low-cost external components
• EMI compliance for EN55022/CISPR22
• Standby power less than 20mW
• No audible noise

Specifications

This board is optimized for the following operating conditions:

• Input voltage: 85VAC ~ 265VAC
• Output voltage: 12VDC
• Output current: 667mA max
• Output power: 8W
• Efficiency: >77% at 100% load; 80% at 50% load
• No-load power: 14mW at 120VAC; 16mW at 230VAC
• Load regulation: ±2.4%, load range 10% to 100%
• Operating temperature: -40~85°C
• Board dimension: 40mm x 60mm.

Table 1. HV Buck of 021 Power Derating at 85°C Ambient Temperature

Table 2. Component Selection Guide

Functional Description

The RTKA223021DE0000BU is a buck regulator implemented with a high-side float-switching topology, with a switching frequency up to 43kHz. D1 is a full bridge rectifier on the input end. FR is a 1A fuse providing input overcurrent protection. As an option, you can replace the standard fuse with a fusible resistor instead to limit inrush current.
C1, L1, and C2 consist of the input filter that provides the energy buffer after rectification and reduces conducted EMI noises to the input. L2, D2, and COUT are the buck converter components. RFB1, RFB2, CFB2, and CFB1 provide the output feedback signal to the IC. D4 and R2 provide VCC biasing current after startup to increase efficiency. They can be optional for low-cost low-power applications. CVCC is the IC supply capacitor.

1.1 Recommended Equipment and Operating Range

• AC Power supply capable of generating AC voltage from 85VAC to 265VAC at 60Hz/50Hz, with at least 100mA output current capability.
• Load resistor box with an adjustable value of 18Ω and up, or an electronics load that can emulate a resistor load or current load up to 667mA.
• Multi-meters to measure the output voltage and current.
• Power meter to measure the AC input power.

1.2 Setup and Configuration

1. Program the AC power supply with a voltage between 85VAC and 265VAC at the corresponding frequency of 60Hz or 50Hz.
2. While the AC power supply is off, connect the output cables of the AC power supply to the L and N terminal of the RTKA223021DE0000BU. An optional power meter can be added in between the AC power supply output and the input of the board.
3. Connect the load to the output terminals VOUT and GND.
4. Connect a voltage meter to VOUT and GND and connect a current meter between the board outputs and the load.
5. Turn on the AC power supply.

Board Design

2.1 Layout Guidelines

Proper layout is important to ensure a stable operation, good thermal behavior, EMI performance, and reliable operation for various operating environments. Please pay attention to the following layout recommendations.

• Leave proper spacing (minimum1.4mm) between high voltage (max 400V) traces and low voltage traces.
• Keep a small loop from the input filter capacitor to IC, switching inductor, output capacitor, and to the ground of the input capacitor.
• Keep a small loop consisting of a switching inductor, output capacitor, and freewheeling diode.
• Keep a small loop consisting of an input filter capacitor to IC and a freewheeling diode.
• Keep sufficient copper area on the IC drain and/or source pin (not less than 140mm2 for 6-8W output power) for better thermal performance.
• Keep the switching inductor away from the input EMI inductor to avoid noise coupling, especially when an unshielded switching inductor is used.
• Keep a small loop from the input filter capacitor to IC, sample hold circuit, output capacitor, and to the ground of the input capacitor.
• Place the VCC decoupling cap and FB pin decoupling cap close to the pins.

2.2 Schematic Diagrams

2.3 Bill of Materials

2.4 Board Layout

Typical Performance Graphs

VOUT = 12V, unless otherwise noted.

EMI Test Result

Conducted EMI compliance for EN55022/CISPR22 (12V/600mA output)

Ordering Information

Revision History

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References

• Renesas Electronics Corporation
• Contact Us | Renesas
• Renesas Electronics Corporation
• Contact Us | Renesas
• RAA223021 - 700V AC/DC Regulator with Ultra-Low Standby Power and up to 8W Output Power | Renesas