AN2872
Application note
Super wide-range buck converter based on the VIPer16
1
Introduction
This document describes the STEVAL-ISA010V1 demonstration board, which is designed
as an example of a simple non-isolated auxiliary power supply for a range of input voltages
from 85 VAC to 500 VAC.
There is an ever-increasing demand for small power supplies capable of working without
voltage range limitations, even at nominal levels of 400 VAC and 415 VAC, respectively. The
real voltage levels can reach 500 VAC (415 V + 20%). The major markets for this type of
SMPS are home appliances and metering.
The new STMicroelectronics™ family of monolithic converters is well-suited for this range of
input voltages, thanks to the 800 V avalanche-rugged MOSFET integrated within the same
package with the control chip. This application note describes a low power SMPS with
a buck topology using STMicroelectronics’ VIPer16 fixed-frequency off-line converter as
a main circuit. The VIPer16 device includes an 800 V rugged power switch, a PWM
controller, programmable overcurrent, overvoltage, overload, a hysteretic thermal protection,
soft-start and safe auto-restart after any fault condition removal. Burst mode operation at
light load combined with the very low consumption of the device helps to meet standby
energy-saving regulations. The significant benefit of this new chip derives from the jitter of
the switching frequency and the possibility to supply the chip directly from the DC HV bus,
so auxiliary supply is not mandatory. The VIPer16 is suitable for flyback or buck topologies,
and thanks to an internal self-supply circuit it does not require an auxiliary supply.
Figure 1.
The STEVAL-ISA010V1 demonstration board
April 2009
Doc ID 15305 Rev 1
1/23
www.st.com
Contents
AN2872
Contents
1
2
3
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Main characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.1
Theory of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.1.1
3.1.2
The basic principle of the buck converter . . . . . . . . . . . . . . . . . . . . . . . . 6
Practical aspects of a buck converter dedicated for mains
and 3-phase input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.2
3.3
3.4
Converter schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
PCB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Bill of material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4
Experimental results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.1
4.2
4.3
4.4
4.5
4.6
Load regulation and output voltage ripple . . . . . . . . . . . . . . . . . . . . . . . . 13
Standby . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
MOSFET voltage stress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Short-circuit behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
EMC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.6.1
4.6.2
4.6.3
Surge - IEC 61000-4-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Burst - IEC 61000-4-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
EMI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.7
Thermal behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5
6
7
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
2/23
Doc ID 15305 Rev 1
AN2872
List of tables
List of tables
Table 1.
Table 2.
Table 3.
List of components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Temperature of the VIPer16 at full load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Doc ID 15305 Rev 1
3/23
List of figures
AN2872
List of figures
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Figure 9.
Figure 10.
Figure 11.
Figure 12.
Figure 13.
The STEVAL-ISA010V1 demonstration board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Buck converter schematic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Standard implementation of a buck converter with a monolithic device . . . . . . . . . . . . . . . . 8
Schematic of the step-down converter based on the VIPer16L . . . . . . . . . . . . . . . . . . . . . . 9
PCB layout of the buck converter (top, bottom, bottom layout) . . . . . . . . . . . . . . . . . . . . . 11
12 V output load regulation for different output loads and input voltage levels
(linear regulator U2 not assembled) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Output voltage ripple for different input voltages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Alternative schematic of the input part using balancing Zener diodes instead of
resistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Standby consumption for different input voltage levels . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Efficiency of the converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Drain voltage (CH1) and inductor current (CH4) at different input voltages . . . . . . . . . . . . 17
Indication of current (CH4) and drain voltage (CH1) during short-circuit . . . . . . . . . . . . . . 18
EMI measurements of the demonstration board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4/23
Doc ID 15305 Rev 1
AN2872
Main characteristics
2
Main characteristics
The main characteristics of the SMPS are listed below:
●
Input:
–
–
V
IN
: 85 - 500 VAC
f: 45 - 66 Hz
12 V ± 10%
5 V ± 4%
150 mA total (5 V and 12 V output) output current for full input voltage range
●
Output:
–
–
–
●
●
●
Standby: 96 mW at 230 VAC
Short-circuit: protected
PCB type and size:
–
–
–
FR4
Single side 70 µm
27 x 45 mm
●
●
●
●
Isolation: non isolated - N connected to output GND
EMI: In accordance with EN55022 - class B
EMC: Surge - IEC 61000-4-5 - 2 kV
EMC: Burst - IEC 61000-4-4 - 8 kV
Doc ID 15305 Rev 1
5/23
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
