AN728 VISHAY | Alldatasheet
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amplified and transferred to the output. values to locate the low-frequency power stage filter pole. input is proportional to square of peak primary current (I-pk).
2 LP/C0466IPK /C04672 fs
2 LP/C0466IPK /C0068IPK /C04672 fs /C0104
FIGURE 4. Calculated Loop Gain
FIGURE 5. Measured Loop Gain Introduce the error amplifier low–frequency zero at 47 Hz. capacitor ESR zero location. the error amplifier zero the phase margin can be estimated. 20 kHz, dc losses in the winding will usually be dominant. though these are very low at lower switching frequencies. choice for this application.
to keep the control circuit operating current at low level. be dissipated in the internal depletion MOSFET. on calculating power loss in the converter.
3.96 M/C0087
1 M/C0087
5.1 M/C0087
40 V/12 mA
3.3 V/120 mA
FIGURE 6. Dual Output Flyback converter with Tightly Regulated Main Output
www.vishay.com /C0083 FaxBack 408-970-5600 Document Number: 71120 29-Feb-00 /C0084/C0069 /C0080/C0079/C0087/C0069/C0082 /C0083/C0084/C0065/C0084/C0069/C0083 Two states exist in which power is supplied to TE: normal and restricted. The state determines the maximum power levels supplied to TE by the power sources. Under normal conditions, PS1 will deliver up to 1 W of power to an activated terminal on the S-interface. The restricted condition may be enforced under emergency conditions when the network or NT is forced to supply power in the event of a mains supply failure. When supplying power via PS1, NT indicates this condition to TE by reversing the voltage polarity. This causes the attached TEs to enter a restricted mode of operation in which the designated TE can consume only 380 mW of power to remain operable. The power capabilities of PS1 and PS2 in normal and restricted modes are given in Table 1. /C0084/C0065/C0066/C0076/C0069 /C0032/C0049/C0032/C0046 /C0080/C0079/C0087/C0069/C0082 /C0083/C0079/C0085/C0082/C0067/C0069/C0083 /C0083/C0080/C0069/C0067/C0073/C0070/C0073/C0067/C0065/C0084/C0073/C0079/C0078 Condition Power Source 1 ITU-T/ETSI, Nominal 40 V Power Source 2 ITU-T/ETSI, Nominal 40 V Voltage/Power at NT in Normal Mode 34 to 42 V at up to max. power (1 W) 42-V max. Min defined by TE requirements. Max. power 8 W(ETSI-7 W) Voltage/Power at NT in Restricted Mode 34 to 42 V at up to 420 mW 42-V max. Min defined by TE requirements. Min. power 2 W Voltage/Power at TE in Normal Mode 24 to 42 V at up to 1 W 32 to 42 V at min. power of 7 W Voltage/Power at TE in Restricted Mode32 to 42 V at up to 401 mW. (380 mW for a designated at TE plus 21 mW for all other TEs combined) 32 to 42 V at min. power of 2 W /C0066/C0073/C0066/C0076/C0073/C0079/C0071/C0082/C0065/C0080/C0072/C0089 1. Nick Burd, The ISDN subscriber loop; Chapman & Hall 2. Power Integrated Circuit; Vishay Siliconix 3. Switching Power Supply Design; Abraham Pressman 4. G Dicenet, Design and prospects for the ISDN; Artech House 5. ETS 300 012-1 Integrated Services Digital Network (ISDN), Basic User Network Interface (UNI) Part 1: Layer 1 specification; ETSI 6. ETR 080 Transmission and Multiplexing (TM); Integrated Services Digital Network (ISDN) basic rate access; Digital transmission system on metallic local lines; ETSI