VIPER37LE

Manufacturer Part NumberVIPER37LE
DescriptionAC/DC Switching Converters ViperPlus Fixed Freq 800V 30mQ 265 Vac
ManufacturerSTMicroelectronics
TypeOff Line Switcher
VIPER37LE datasheet
 


Specifications of VIPER37LE

Product CategoryAC/DC Switching ConvertersInput / Supply Voltage (max)23.5 V
Input / Supply Voltage (min)8.5 VSwitching Frequency60 kHz
Supply Current2.5 mAOperating Temperature Range- 40 C to + 150 C
Mounting StyleThrough HolePackage / CaseSDIP-10
Maximum Operating Temperature+ 125 CMinimum Operating Temperature- 25 C
Number Of Outputs1Output Power25 W
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VIPerPlus family: fixed frequency offline converter
Features
800 V avalanche rugged power section
PWM operation with adjustable limiting current
30 mW standby power at 265 Vac
Operating frequency:
– 60 kHz for L type
– 115 kHz for H type
Frequency jittering for low EMC
Output overvoltage protection
High primary current protection (2
Input undervoltage setting (brownout)
Onboard soft-start
Safe auto-restart after a fault condition
Hysteretic thermal shutdown
Applications
SMPS for set-top boxes, DVD players and
recorders, white goods
Auxiliary power supply for consumer and home
equipment
ATX auxiliary power supply
Low / medium power AC-DC adapters
Table 1.
Device summary
Order codes
VIPER37LE
VIPER37HE
February 2012
SDIP10
Description
This device is an offline converter with an 800 V
rugged power section, a PWM control, two levels
of overcurrent protection, overvoltage and
nd
OCP)
overload protection, hysteretic thermal protection,
soft-start, and safe auto-restart after the removal
of any fault condition. Burst mode operation and
very low device consumption help to meet the
standby energy saving regulations.
Advance frequency jittering reduces EMI filter
costs. Brownout 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 startup
circuit is embedded in the device.
Figure 1.
+
DC input high voltage
wide range
DRAIN
DRAIN
DRAIN DRAIN DRAIN
VIPER37
GND
VDD
CONT
Package
SDIP10
Doc ID 022218 Rev 1
VIPER37
Typical topology
DC Output voltage
FB
BR
Packaging
Tube
www.st.com
+
-
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VIPER37LE Summary of contents

  • Page 1

    ... Auxiliary power supply for consumer and home equipment ■ ATX auxiliary power supply ■ Low / medium power AC-DC adapters Table 1. Device summary Order codes VIPER37LE VIPER37HE February 2012 SDIP10 Description This device is an offline converter with an 800 V rugged power section, a PWM control, two levels of overcurrent protection, overvoltage and nd ...

  • Page 2

    Contents Contents 1 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

  • Page 3

    VIPER37 9 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

  • Page 4

    Block diagram 1 Block diagram Figure 2. Block diagram BRth 15uA SOFT START CONT . OVP LOGIC 6uA OVP FB 2 Typical power Table 2. Typical power Part number Adapter VIPER37 1. Typical continuous power in ...

  • Page 5

    VIPER37 3 Pin settings Figure 3. Connection diagram (top view) Note: The copper area for heat dissipation must be designed under the DRAIN pins. Table 3. Pin description Pin n. Name 1 GND 2 VDD 3 CONT ...

  • Page 6

    Electrical data 4 Electrical data 4.1 Maximum ratings Table 4. Absolute maximum ratings Symbol V Drain-to-source (ground) voltage DRAIN Repetitive avalanche energy E AV (limited by T Repetitive avalanche current I AR (limited Pulse drain current DRAIN ...

  • Page 7

    VIPER37 4.3 Electrical characteristics (T = -25 to 125 ° Table 6. Power section Symbol V Breakdown voltage BVDSS I OFF state drain current OFF Drain-source on state R DS(on) resistance Effective (energy related) C OSS output capacitance ...

  • Page 8

    Electrical data Table 7. Supply section Symbol Voltage Drain-source start voltage V DRAIN _START I Startup charging current DDch V Operating voltage range DDclamp DDon DDoff shutdown threshold V DD ...

  • Page 9

    VIPER37 Table 8. Controller section Symbol Feedback pin Overload shutdown V FBolp threshold V Linear dynamics upper limit FBlin V Burst mode threshold FBbm V Burst mode hysteresis FBbmhys I Feedback sourced current FB R Dynamic resistance FB(DYN) ∆V H ...

  • Page 10

    Electrical data Table 8. Controller section (continued) Symbol Overcurrent protection (2 Second overcurrent I DMAX threshold Overvoltage protection Overvoltage protection V OVP threshold Overvoltage protection T STROBE strobe time Brownout protection V Brownout threshold BRth Voltage hysteresis above V BRhyst ...

  • Page 11

    VIPER37 Figure 4. Minimum turn-on time test circuit 14 V Figure 5. Brownout threshold test circuits Figure 6. OVP threshold test circuits 14 V Note: Adjust V above V DD GND DRAIN VDD DRAIN CONT DRAIN ...

  • Page 12

    Typical electrical characteristics 5 Typical electrical characteristics Figure 7. Current limit vs. T Figure 9. Drain start voltage vs. T 12/35 Figure 8. J Figure 10. HFB vs Doc ID 022218 Rev 1 VIPER37 Switching frequency vs. T ...

  • Page 13

    VIPER37 Figure 11. Brownout threshold vs. T Figure 13. Brownout hysteresis current vs. T Typical electrical characteristics Figure 12. Brownout hysteresis vs Figure 14. Operating supply current J (not switching) vs. T Doc ID 022218 Rev 1 J ...

  • Page 14

    Typical electrical characteristics Figure 15. Operating supply current (switching) vs. T Figure 17. Power MOSFET ON resistance vs 14/35 Figure 16. Current limit vs Figure 18. Power MOSFET breakdown voltage Doc ID 022218 Rev 1 VIPER37 ...

  • Page 15

    VIPER37 Figure 19. Thermal shutdown Typical electrical characteristics Doc ID 022218 Rev 1 15/35 ...

  • Page 16

    Typical circuit 6 Typical circuit Figure 20. Min-features flyback application Figure 21. Full-features flyback application 16/ Vcc V DRAIN DD BR CONTROL ...

  • Page 17

    VIPER37 7 Efficiency performances for a typical flyback converter The efficiency of the converter has been measured in different load and line voltage conditions. In accordance with the ENERGY STAR method, the efficiency measurements have been performed at 25%, 50% ...

  • Page 18

    Efficiency performances for a typical flyback converter Figure 23. Power supply consumption at no output load, V 18/ brownout 55 With brownout 100 150 Input voltage [Vac] ...

  • Page 19

    VIPER37 8 Operation description The device is a high-performance low-voltage PWM controller chip with an 800 V avalanche rugged power section. The controller includes: the oscillator with jittering feature, the startup circuits with soft-start feature, the PWM logic, the current ...

  • Page 20

    Operation description 8.3 Power-up and soft-start If the input voltage rises up to the device start threshold V begins to grow due to the I startup circuit. If the V MOSFET starts switching and the HV current generator is turned ...

  • Page 21

    VIPER37 Figure 24. I current during startup and burst mode DD Figure 25. Timing diagram: normal power-up and power-down sequences Doc ID 022218 Rev 1 Operation description 21/35 ...

  • Page 22

    Operation description Figure 26. Timing diagram: soft-start I DRAIN I Dlim FBolp V FBlin 8.4 Power down operation At converter power down, the system loses regulation as soon as the input voltage is so low that the ...

  • Page 23

    VIPER37 Figure 27. Timing diagram: behavior after short-circuit 8.6 Oscillator The switching frequency is internally fixed to 60 kHz or 115 kHz. In both cases the switching frequency is modulated by approximately ±4 kHz (60 kHz version) or ±8 kHz ...

  • Page 24

    Operation description 8.8 Overvoltage protection (OVP) The device can monitor the converter output voltage. This operation is done by the CONT pin during Power MOSFET OFF-time, when the voltage generated by the auxiliary winding tracks the converter's output voltage, through ...

  • Page 25

    VIPER37 The resistor values are such that the current sourced and sunk by the CONT pin are within the rated capability of the internal clamp. Figure 28. OVP timing diagram VAUX 0 0 CONT (pin 4) ...

  • Page 26

    Operation description Table 11. CONT pin configurations Function / component I Dlim I reduction + OVP Dlim 1. R must be fixed before R LIM 8.10 Feedback and overload protection (OLP) The device is a current mode converter: the feedback ...

  • Page 27

    VIPER37 After the startup time, t capacitor may not be at its nominal value and the controller interprets this situation as an overload condition. In this case, the OLP delay helps to avoid an incorrect device shutdown during the startup ...

  • Page 28

    Operation description Figure 30. FB pin configuration 1 Figure 31. FB pin configuration 2 8.11 Burst mode operation at no load or very light load When the load decreases, the feedback loop reacts by lowering the feedback pin voltage. If ...

  • Page 29

    VIPER37 Figure 32. Burst mode timing diagram, light load management 8.12 Brownout protection Brownout protection is a not-latched shutdown function activated when a condition of mains undervoltage is detected. The brownout comparator is internally referenced to V the voltage applied ...

  • Page 30

    Operation description Figure 33. Brownout protection: BR external setting and timing diagram When the V and the V INon relationships can be established for the calculation of the resistors R Equation 9 Equation 10 For a proper operation of this ...

  • Page 31

    VIPER37 In order to enable the brownout function, the BR pin voltage must be higher than the maximum V threshold (150 mV), see DIS nd 8.13 2 level overcurrent protection and hiccup mode The device is protected against short-circuit of ...

  • Page 32

    Package mechanical data 9 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 ...

  • Page 33

    VIPER37 Figure 35. SDIP10 mechanical drawing Doc ID 022218 Rev 1 Package mechanical data 33/35 ...

  • Page 34

    Revision history 10 Revision history Table 13. Document revision history Date 17-Feb-2012 34/35 Revision 1 Initial release Doc ID 022218 Rev 1 VIPER37 Changes ...

  • Page 35

    ... VIPER37 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. ...