Datasheet

ManualsBrandsSTMICROELECTRONICS ManualsPMICsPMIC - AC/DC converter, offline switcher DIP 8

December 2010 Doc ID 11977 Rev 2 1/21

VIPER12A-E

Low power offline switched-mode power supply primary switcher

Features

■ Fixed 60 kHz switching frequency

■ 9 V to 38 V wide range V

voltage

■ Current mode control

■ Auxiliary undervoltage lockout with hysteresis

■ High voltage start-up current source

■ Overtemperature, overcurrent and overvoltage

protection with auto-restart

■ Typical power capability

– European (195 - 265 Vac) 8 W for SO-8,

13 W for DIP-8

– European (85 - 265 Vac) 5 W for SO-8,

8 W for DIP-8

Description

The VIPER12A combines a dedicated current

mode PWM controller with a high voltage power

MOSFET on the same silicon chip.

Typical applications cover off line power supplies

for battery charger adapters, standby power

supplies for TV or monitors, auxiliary supplies for

motor control, etc.

The internal control circuit offers the following

benefits: Large input voltage range on the V

accommodates changes in auxiliary supply

voltage (This feature is well adapted to battery

charger adapter configurations), automatic burst

mode in low load condition and overvoltage

protection in HICCUP mode.

Figure 1. Block diagram

DIP-8SO-8

ON/OFF

0.23 V

DRAIN

SOURCE

VDD

PWM

LATCH

60kHz

OSCILLATOR

BLANKING

8/14.5V

REGULATOR

INTERNAL

SUPPLY

OVERVOLTAGE

LATCH

OVERTEMP.

DETECTOR

1 kΩ

42V

230 Ω

www.st.com

Summary of content (21 pages)

PAGE 1
VIPER12A-E Low power offline switched-mode power supply primary switcher Features ■ Fixed 60 kHz switching frequency ■ 9 V to 38 V wide range VDD voltage ■ Current mode control ■ Auxiliary undervoltage lockout with hysteresis ■ High voltage start-up current source ■ Overtemperature, overcurrent and overvoltage protection with auto-restart ■ Typical power capability – European (195 - 265 Vac) 8 W for SO-8, 13 W for DIP-8 – European (85 - 265 Vac) 5 W for SO-8, 8 W for DIP-8 SO-8 Typical applic
PAGE 2
Contents VIPER12A-E Contents 1 Electrical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1 Maximum rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2 Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3 Pin connections and function .
PAGE 3
VIPER12A-E Electrical data 1 Electrical data 1.1 Maximum rating Stressing the device above the rating listed in the “absolute maximum ratings” table may cause permanent damage to the device. These are stress ratings only and operation of the device at these or any other conditions above those indicated in the Operating sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Table 1.
PAGE 4
Electrical characteristics 2 VIPER12A-E Electrical characteristics TJ = 25 °C, VDD = 18 V, unless otherwise specified Table 3. Power section Symbol Parameter BVDSS Drain-source voltage ID = 1 mA; VFB = 2 V OFF State drain current VDS = 500 V; VFB = 2 V; TJ = 125 °C Static drain-source ON state resistance ID = 0.2 A ID = 0.2 A; IDSS rDS(on) Test conditions Min Typ Max 730 Unit V 0.1 27 ID = 0.2 A ID = 0.2 A; TJ = 100 °C 30 mA Ω 54 tf Fall time ID = 0.
PAGE 5
VIPER12A-E Electrical characteristics Table 5. Symbol FOSC Table 6. Symbol Oscillation section Parameter Oscillator frequency total variation Test conditions VDD = VDDoff ... 35 V; TJ = 0 ... 100 °C Min Typ Max Unit 54 60 66 kHz Min Typ Max Unit 0.48 A PWM comparator section Parameter Test conditions GID IFB to ID current gain (See Figure 12 on page 14) IDlim Peak current limitation VFB = 0 V (See Figure 12 on page 14) IFBsd IFB shutdown current (See Figure 12 on page 14) 0.
PAGE 6
Pin connections and function 3 VIPER12A-E Pin connections and function Figure 2. Pin connection SOURCE 1 8 DRAIN SOURCE 1 8 DRAIN SOURCE 2 7 DRAIN SOURCE 2 7 DRAIN FB 3 6 DRAIN FB 3 6 DRAIN VDD 4 5 DRAIN VDD 4 5 DRAIN SO-8 Figure 3. DIP-8 Current and voltage conventions I DD ID VDD I FB FB VDD VFB Table 9. CONTROL VD SOURCE VIPer12A Pin function Pin Name Pin Function VDD Power supply of the control circuits.
PAGE 7
VIPER12A-E 4 Rectangular U-I output characteristics Rectangular U-I output characteristics Figure 4. Rectangular U-I output characteristics for battery charger A complete regulation scheme can achieve combined and accurate output characteristics. Figure 4. presents a secondary feedback through an optocoupler driven by a TSM101. This device offers two operational amplifiers and a voltage reference, thus allowing the regulation of both output voltage and current.
PAGE 8
Wide range of VDD voltage 5 VIPER12A-E Wide range of VDD voltage The VDD pin voltage range extends from 9 V to 38 V. This feature offers a great flexibility in design to achieve various behaviors. In Figure 4 on page 7 a forward configuration has been chosen to supply the device with two benefits: 8/21 ● As soon as the device starts switching, it immediately receives some energy from the auxiliary winding.
PAGE 9
VIPER12A-E 6 Feedback pin principle of operation Feedback pin principle of operation A feedback pin controls the operation of the device. Unlike conventional PWM control circuits which use a voltage input (the inverted input of an operational amplifier), the FB pin is sensitive to current. Figure 5. presents the internal current mode structure. Figure 5. Internal current control structure The power MOSFET delivers a sense current Is which is proportional to the main current Id.
PAGE 10
Feedback pin principle of operation VIPER12A-E The current limitation is obtained with the FB pin shorted to ground (VFB = 0 V). This leads to a negative current sourced by this pin, and expressed by: I FB = – 0.23V ---------------R1 By reporting this expression in the previous one, it is possible to obtain the drain current limitation IDlim: 1 1 I Dlim = G ID ⋅ 0.
PAGE 11
VIPER12A-E 7 Startup sequence Startup sequence Figure 7. Startup sequence This device includes a high voltage start up current source connected on the drain of the device. As soon as a voltage is applied on the input of the converter, this start up current source is activated as long as VDD is lower than VDDon. When reaching VDDon, the start up current source is switched off and the device begins to operate by turning on and off its main power MOSFET.
PAGE 12
Overvoltage threshold 8 VIPER12A-E Overvoltage threshold An overvoltage detector on the VDD pin allows the VIPER12A to reset itself when VDD exceeds VDDovp. This is illustrated in Figure 8., which shows the whole sequence of an overvoltage event. Note that this event is only latched for the time needed by VDD to reach VDDoff, and then the device resumes normal operation automatically. Figure 8.
PAGE 13
VIPER12A-E 9 Operation pictures Operation pictures Figure 9. Rise and fall time Figure 10. Start-up VDD current IDD IDD0 VDDhyst VDDoff IDDch VDD VDDon VDS = 100 V Fsw = 0 kHz Figure 11.
PAGE 14
Operation pictures VIPER12A-E Figure 12. Peak drain current vs feedback current Figure 13.
PAGE 15
VIPER12A-E Operation pictures Figure 14. Switching frequency vs temperature Figure 15.
PAGE 16
Package mechanical data 10 VIPER12A-E Package mechanical data In order to meet environmental requirements, ST offers these devices in different grades of ECOPACK® packages, depending on their level of environmental compliance. ECOPACK® specifications, grade definitions and product status are available at: www.st.com. ECOPACK is an ST trademark.
PAGE 17
VIPER12A-E Package mechanical data Table 10. DIP8 mechanical data Databook (mm) Ref. Min. Nom. A Max. 5.33 A1 0.38 A2 2.92 3.30 4.95 b 0.36 0.46 0.56 b2 1.14 1.52 1.78 c 0.20 0.25 0.36 D 9.02 9.27 10.16 E 7.62 7.87 8.26 E1 6.10 6.35 7.11 e 2.54 eA 7.62 eB L 10.92 2.92 Package Weight 3.30 3.81 Gr. 470 Figure 16.
PAGE 18
Package mechanical data Table 11. VIPER12A-E SO8 mechanical data Databook (mm) Dim. Nom Max A 1.35 1.75 A1 0.10 0.25 A2 1.10 1.65 B 0.33 0.51 C 0.19 0.25 D 4.80 5.00 E 3.80 4.00 e 1.27 H 5.80 6.20 h 0.25 0.50 L 0.40 1.27 k 8° (max.) ddd 0.1 Figure 17.
PAGE 19
VIPER12A-E 11 Order codes Order codes Table 12.
PAGE 20
Revision history 12 VIPER12A-E Revision history Table 13. 20/21 Document revision history Date Revision Changes 09-Jan-2006 1 Initial release. 13-Dec-2010 2 Updated Table 3 on page 4, Table 4 on page 4 and Figure 10 on page 13.
PAGE 21
VIPER12A-E Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale.