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STR-W6765 Datasheet(PDF) 6 Page - Allegro MicroSystems |
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STR-W6765 Datasheet(HTML) 6 Page - Allegro MicroSystems |
6 / 15 page ![]() Quasi-Resonant Topology Primary Switching Regulators STR-W6765 6 ELECTRICAL CHARACTERISTICS Test Conditions* Parameter Test Conditions VCC (V) Measure- ment Circuit Operation Start Voltage VCC voltage at which oscillation starts. 0→20 1 Operation Stop Voltage VCC voltage at which oscillation stops. 20→8.8 Circuit Current In Operation Inflow current flowing into power supply terminal in oscillation. 20 Circuit Current In Non-operation Inflow current flowing into power supply terminal prior to oscillation. 15 Oscillation Frequency Oscillating frequency ( fosc= 1 / T ). 20 Soft Start Operation Stop Voltage SS/OLP terminal voltage at which ISS/OLP reach ≥–100 μA by raising the SS/OLP terminal voltage from 0 V gradually. 20 5 Soft Start Operation Charging Current SS/OLP terminal charging current (SS/OLP terminal voltage = 0 V). Bottom-Skip Operation Threshold Voltage 1 Input 1 μs pulse width, as shown in waveform 1, to OCP/BD terminal twice after V1-3 rises. After that, offset the input waveform gradually from 0 V in the minus direction. Measurment of the offset voltage VOCPBD(BS1) is taken when the V1-3 start-to-fall point switches from two- pulses-after to one-pulse-after. 20 3 Bottom-Skip Operation Threshold Voltage 2 After measuring VOCPBD(BS1), as shown in waveform 2, offset the input waveform gradually. Measurment of the offset voltage VOCPBD(BS2) is taken when the V1-3 start-to-fall point switches from two-pulses-after to one-pulse-after. Overcurrent Detection Threshold Voltage OCP/BD terminal voltage at which oscillation stops by lowering the OCP/BD terminal voltage from 0 V gradually. 20 2 OCP/BDOCP/BD Terminal Outflow Current OCP/BD terminal outflow current (OCP/BD terminal voltage = –0.95 V). Quasi-Resonant Operation Threshold Voltage 1 OCP/BD terminal voltage at which oscillation starts with setting the OCP/BD terminal voltage at 1 V, and then lowering the voltage gradually. Quasi-Resonant Operation Threshold Voltage 2 OCP/BD terminal voltage at which oscillation stops by raising the OCP/BD terminal voltage from 0 V gradually. FB Terminal Threshold Voltage FB terminal voltage at which oscillation stops by raising the FB terminal voltage from 0 V gradually. 20 4 FB Terminal Inflow Current (Normal Operation) FB terminal inflow current (FB terminal voltage = 1.6 V). 20 Standby Operation Start Voltage VCC voltage at which ICC reaches ≥1 mA (FB terminal voltage = 1.6 V). 0→15 Standby Operation Start Voltage Interval Specified by VCC(SK) = VCC(S) – VCC(OFF).– Standby Non-Operation Circuit Current Inflow current flowing into power supply terminals prior to oscillation (FB terminal voltage = 1.6 V). 10.2 FB Terminal Inflow Current, Standby Operation FB terminal inflow current (FB terminal voltage = 1.6 V). 10.2 FB Terminal Threshold Voltage Standby Operation FB terminal voltage at which oscillation starts by raising the FB terminal voltage from 0 V gradually. 15 Minimum On Time Waveform between terminals 1 and 3 at low. 20 6 Maximum On Time Waveform between terminals 1 and 3 at low. 20 1 Continued on the next page… Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com |