VIPER25

Manufacturer Part NumberVIPER25
DescriptionVIPerPlus family: quasi-resonant high performance off line high voltage converter
ManufacturerSTMicroelectronics
VIPER25 datasheet
 


1
Page 1
2
Page 2
3
Page 3
4
Page 4
5
Page 5
6
Page 6
7
Page 7
8
Page 8
9
Page 9
10
Page 10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
Page 1/40

Download datasheet (2Mb)Embed
Next
Features
800 V avalanche rugged power section
Quasi-resonant (QR) control for valley
switching operation
Standby power < 50 mW at 265 Vac
Limiting current with adjustable set point
Adjustable and accurate overvoltage
protection
On-board soft-start
Safe auto-restart after a fault condition
Hysteretic thermal shutdown
Applications
Adapters for PDA, camcorders, shavers,
cellular phones, cordless phones, videogames
Auxiliary power supply for LCD/PDP TV,
monitors, audio systems, computer, industrial
systems, LED driver, No el-cap LED driver,
utility power meter
SMPS for set-top boxes, DVD players and
recorders, white goods
Table 1.
Device summary
Order codes
VIPER25LN / VIPER25HN
VIPER25HD / VIPER25LD
VIPER25HDTR / VIPER25LDTR
July 2010
Off-line high voltage converters
SO16 narrow
SO-16
Description
The device is an off-line converter with an 800 V
rugged power section, a PWM control, double
levels of overcurrent protection, overvoltage and
overload protections, hysteretic thermal
protection, soft-start and safe auto-restart after
any fault condition removal. Burst mode operation
and device very low consumption helps to meet
the standby energy saving regulations. The quasi-
resonant feature reduces EMI filter cost. Brown-
out and brown-in function protects the switch
mode power supply when the rectified input
voltage level is below the normal minimum level
specified for the system. The high voltage start-up
circuit is embedded in the device.
Figure 1.
Typical topology
Package
DIP-7
SO16 narrow
Doc ID 15585 Rev 4
VIPER25
DIP-7
Packaging
Tube
Tube
Tape and reel
1/40
www.st.com
40

VIPER25 Summary of contents

  • Page 1

    ... SMPS for set-top boxes, DVD players and recorders, white goods Table 1. Device summary Order codes VIPER25LN / VIPER25HN VIPER25HD / VIPER25LD VIPER25HDTR / VIPER25LDTR July 2010 Off-line high voltage converters SO16 narrow SO-16 Description The device is an off-line converter with an 800 V rugged power section, a PWM control, double ...

  • Page 2

    ... Double blanking time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 7.9 Starter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 7.10 Current limit set point and feed-forward option . . . . . . . . . . . . . . . . . . . . . 24 7.11 Overvoltage protection (OVP 7.12 Summary on ZCD pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 7.13 Feedback and overload protection (OLP 7.14 Burst-mode operation at no load or very light load . . . . . . . . . . . . . . . . . . 32 7.15 Brown-out protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 7.16 2nd level over current protection and hiccup mode . . . . . . . . . . . . . . . . . 34 2/40 Doc ID 15585 Rev 4 VIPER25 ...

  • Page 3

    ... VIPER25 8 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Doc ID 15585 Rev 4 Contents 3/40 ...

  • Page 4

    ... Typical continuous power in non ventilated enclosed adapter measured at 50 °C ambient. 2. Maximum practical continuous power in an open frame design at 50 °C ambient, with adequate heat sinking. 4/40 230 V AC (1) (2) Adapter Open frame Doc ID 15585 Rev 4 VIPER25 85-265 V AC (1) (2) Adapter Open frame ...

  • Page 5

    ... VIPER25 3 Pin settings Figure 3. Connection diagram (top view) Note: The copper area for heat dissipation has to be designed under the DRAIN pins. Table 3. Pin description Pin n. Name DIP-7 SO16 1 1...2 GND - 4 N. VDD 3 6 ZCD 7,8 13...16 DRAIN This pin represents the device ground and the source of the power section. ...

  • Page 6

    ... Max. 800 5 1.5 = 150 ° mA) -0.3 Self limited -0.3 5.5 = 0.5 mA) -0.3 Self limited BR -0.3 Self limited 25 1 1.5 -40 150 -55 150 Max. value Max. value SO16N DIP7 100 50 80 (0.155 sq in (35 μm thick) 2 VIPER25 Unit °C °C Unit °C/W °C/W °C/W ...

  • Page 7

    ... VIPER25 4.3 Electrical characteristics (T = -25 to 125 ° Table 6. Power section Symbol V Break-down voltage BVDSS I OFF state drain current OFF Drain-source on state R DS(on) resistance Effective (energy related) C OSS output capacitance Table 7. Supply section Symbol Voltage Drain-source start voltage V DRAIN _START I Start-up charging current ...

  • Page 8

    ... Typ. 4.5 4.8 3.2 3.3 0.6 100 = 0.3 V -150 -200 < 4 < 3 5.5 0.8 0.6 -10 < 6.3 > -10 µA 0.66 0.7 7.5 9.5 220 400 100 300 = 0.6 V 160 1.2 3.8 4.2 2.2 VIPER25 Max. Unit 5 -280 kΩ µA µs µs 0.74 A 3 480 4.6 V μs ...

  • Page 9

    ... BRhyst V BRth I Current hysteresis BRhyst V Clamp voltage BRclamp V Brown-out disable voltage DIS Thermal shutdown Thermal shutdown T SD temperature T Thermal shutdown hysteresis HYST Parameter Test condition VIPER25L VIPER25H <V ZCD ZCDT th t< <V ZCD ZCDT th t>t SU VFB = > V ZCD ...

  • Page 10

    ... V DDon Doc ID 15585 Rev 4 V DRAIN ONmin DRAIN I Dlim BRth +V BRhyst V BRth V DIS kΩ I BRhyst I DRAIN ZCD V OVP 10 kΩ V DRAIN 30 V VIPER25 Time Time Time Time Time Time Time ...

  • Page 11

    ... VIPER25 5 Typical electrical characteristics Figure 7. Current limit vs T Figure 9. HFB vs T Figure 11. Brown-out hysteresis vs T Figure 8. J Figure 10. Brown-out threshold Figure 12. Brown-out hysteresis current J Doc ID 15585 Rev 4 Typical electrical characteristics Drain start voltage 11/40 ...

  • Page 12

    ... ZCD 500 450 400 350 300 0.0 50.0 Figure 17. Power MOSFET on-resistance vs T 12/40 Figure 14. Operating supply current Figure 16. Current limit vs I ZCD 100.0 150.0 200.0 250.0 I (μA) ZCD Figure 18. Power MOSFET break down J Doc ID 15585 Rev 4 VIPER25 (switching ZCD voltage ...

  • Page 13

    ... VIPER25 Figure 19. Thermal shutdown DDon V DDoff V DD(RESTART) I DRAIN HYST SD Normal operation Typical electrical characteristics Shut down after over temperature Doc ID 15585 Rev 4 time time time Normal operation 13/40 ...

  • Page 14

    ... Typical circuits 6 Typical circuits Figure 20. Min-features QR flyback application Figure 21. Full-features QR flyback application 14/40 Doc ID 15585 Rev 4 VIPER25 ...

  • Page 15

    ... VIPER25 7 Operation description VIPER25 is a high-performance low-voltage PWM controller IC with an 800 V, avalanche rugged power section. The controller includes the current-mode PWM logic and the ZCD (zero current detect) circuit for QR operation, the start-up circuitry with soft-start feature, an oscillator for frequency foldback function, the current limit circuit with adjustable set point, the second overcurrent circuit, the burst mode management circuit, the brown-out circuit, the UVLO circuit, the auto-restart circuit and the thermal shutdown circuit ...

  • Page 16

    ... During normal operation, the power MOSFET is switched ON immediately after transformer demagnetization, detected by the VIPER25, through the voltage V pin. At power up the initial output voltage is zero and then the voltage V enough to correctly arm the internal ZCD circuit. In this case, the power MOSFET is turned ON with a fixed frequency determined by the internal oscillator ...

  • Page 17

    ... VIPER25 As soon as the output voltage reaches the regulated value, the regulation loop takes over and the drain current is regulated below its limit value lower than the threshold V Figure 22. I current during start-up and burst mode DDon V DDoff V FB ...

  • Page 18

    ... FB V FBolp V FBlin V OUT Regulated value Figure 25. Timing diagram: Start-up phase and soft start (case 2) t (start up phase DRAIN t (soft start Dlim FBolp V FBlin V OUT Regulated value 18/40 (start up phase) (soft start) SS Doc ID 15585 Rev 4 VIPER25 OLP-delay t t ...

  • Page 19

    ... VIPER25 7.4 Power-down description At converter power-down, the system loses regulation as soon as the input voltage is so low that the peak current limitation is reached. The V the V threshold the power MOSFET is switched OFF, the energy transfers to the IC is DDoff interrupted and consequently the V if the V ...

  • Page 20

    ... Operation description 7.6 Quasi-resonant operation The control core of the VIPER25 is a current-mode PWM controller with a the zero current detection circuit designed for Quasi-Resonant (QR) operation, a technique that provides the benefits of minimum turn-on losses, low EMI emission and safe behavior in case of short circuit. At heavy load the converter operates in quasi-resonant mode: operation lies in synchronizing MOSFET's turn-on to the transformer’ ...

  • Page 21

    ... VIPER25 Figure 27. Switching frequency vs output load Figure 28. Zero current detection circuit and oscillator circuit Doc ID 15585 Rev 4 Operation description 21/40 ...

  • Page 22

    ... The switching frequency increases when the load decreases, or when the input voltage mains increases, and vice versa. In principle it could reach an infinite value. To avoid that, the VIPER25 taps the maximum switching frequency of the application by its control logic. ...

  • Page 23

    ... VIPER25 7.8 Double blanking time The blanking time, T value) and the higher one is 6,3 μs (typical value). The value is linked to the voltage V sampled during the time T relevant Section 7.11 on page 26 < has the higher value if is detected V Figure 30 on page 23 The higher value of the blanking time is normally activated during the start-up phase or in case of output short circuit ...

  • Page 24

    ... Current limit set point and feed-forward option The VIPER25 is a current mode converter and the drain current is limited cycle by cycle according to the FB pin voltage value that is related with the feedback loop response and the load. When the drain current, sensed by the integrated Sense-FET, reaches the current limitation, after the internal propagation delay, the MOSFET is switched OFF ...

  • Page 25

    ... VIPER25 Figure 31. Typical power capability vs input voltage in quasi-resonant converter’s In order to proper select the value of the resistance R are known the proper I voltage. The following approximated formula calculates the value of the resistor R Equation 3 Where: ● V and V in_Max ● the primary to auxiliary winding turn ratio aux ● ...

  • Page 26

    ... Operation description Figure 32. ZCD pin typical external configuration 7.11 Overvoltage protection (OVP) The VIPER25 has integrated the logic for the monitor of the output voltage using as input signal the voltage V the voltage from the auxiliary winding tracks the output voltage, through the turn ratio N N ...

  • Page 27

    ... VIPER25 Equation 6 Where: ● the OVP threshold (see OVP ● the converter output voltage value to activate the OVP (set by designer) OUT OVP designer ● the auxiliary winding turns AUX ● the secondary winding turns SEC ● the secondary diode forward voltage DSEC ● ...

  • Page 28

    ... See equation 7 See Equation 3 Required for ZCD See Equation 3 See equation 7 See Equation 3 ) are respectively the low Figure 2 on page 4 and , in parallel with the PWM , see Figure 36 on page FBolp VIPER25 D OVP Yes Yes Yes Yes Yes Yes Yes Figure 20 the FBlin . FB ...

  • Page 29

    ... VIPER25 The time, from the high load detection, V depends from the value of the capacitor C OLP delay time can be calculating by the formula: Equation 8 The current, I FB, also a part of the compensation loop , so they have to be selected taking into account the proper delay and loop stability consideration. The page 30 show two different feedback networks ...

  • Page 30

    ... Using the alternative compensation network, the designer can FB PWM CONTROL Cfb BURST-MODE REFERENCES 4.8V PWM CONTROL Rfb1 Cfb Cfb1 BURST-MODE REFERENCES Doc ID 15585 Rev 4 VIPER25 ) DYN ) Table 8 on results much higher than C FB1 has to be FB1 From sense FET PWM To PWM Logic + ...

  • Page 31

    ... VIPER25 Figure 36. Timing diagram: Overload protection I OUT V OUT I DRAIN I Dlim FBolp V FBlin SOFT START OVER LOAD Warning START UP Doc ID 15585 Rev 4 Operation description OVER LOAD STOP Warning OPERATION 31/40 ...

  • Page 32

    ... Figure 5 on page 10 , and the rectified input voltage below which the power MOSFET is INon . Thanks to the I , see Table 8 on page 8 BRhyst Doc ID 15585 Rev 4 + FBbm , reported on Table 8 . BRth Figure 38 on page The designer BRhyst , these two thresholds can VIPER25 time time time . A ...

  • Page 33

    ... VIPER25 Figure 38. Brown-out protection: BR external setting and timing diagram VDD V IN_DC BRhyst Fixed the V and the V INon can be established for the calculation of the resistors R Equation 12 Equation 13 For a proper operation of this function, V minimum mains and V minimum mains and maximum load. ...

  • Page 34

    ... DD occurs. If the fault condition is not removed DDon Figure 39 . Secondary diode is shorted here Secondary diode is shorted here Doc ID 15585 Rev 4 , see Table 8 on DMAX capacitor DD ), which clears the latch. voltage goes below its restart voltage, DD VIPER25 ...

  • Page 35

    ... VIPER25 8 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 trademark. Table 10. DIP-7 mechanical data Dim. ...

  • Page 36

    ... Package mechanical data Figure 40. DIP-7 package dimensions 36/40 Doc ID 15585 Rev 4 VIPER25 ...

  • Page 37

    ... VIPER25 Table 11. SO16 narrow mechanical data Dim ccc Databook (mm.) Min. Typ. 0.1 1.25 0.31 0.17 9.8 9.9 5.8 6 3.8 3.9 1.27 0.25 0.4 0 Doc ID 15585 Rev 4 Package mechanical data Max. 1.75 0.25 0.51 0.25 10 6.2 4 0.5 1.27 8 0.1 37/40 ...

  • Page 38

    ... Package mechanical data Figure 41. SO16 package dimensions 38/40 Doc ID 15585 Rev 4 VIPER25 ...

  • Page 39

    ... VIPER25 9 Revision history Table 12. Document revision history Date 17-Apr-2009 09-Jun-2009 26-Aug-2009 21-Jul-2010 Revision 1 Initial release Updated application paragraph in coverpage and 2 page 8 3 Content reworked to improve readability, no technical changes 4 Updated Table 8 on page 8 Doc ID 15585 Rev 4 Revision history Changes Table 8 on and ...

  • Page 40

    ... Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan - Malaysia - Malta - Morocco - Philippines - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States of America 40/40 Please Read Carefully: © 2010 STMicroelectronics - All rights reserved STMicroelectronics group of companies www.st.com Doc ID 15585 Rev 4 VIPER25 ...