NTE7224 Integrated Circuit Quasi−Resonant Topology Primary Switching Regulator Description: The NTE7224 is a quasi−resonant topology integrated circuit in a 7−Lead TO220 type package designed for SMPS applications. This device shows lower EMI noise characteristics than conventional PWM solutions, especially at greater than 2MHz. It also provides a soft−switching operation to turn on the internal MOSFET at close to zero voltage (VDS bottom point) by use of the resonant characteristic of primary inductance and a resonant capacitor. The package is a fully molded TO220, which contains the controller chip (MIC) and MOSFET, enabling output power up to 160W with a 120VAC input. The bottom−skip function skips the first bottom of VDS and turns on the MOSFET at the second bottom point, to minimize an increase of operational frequency at light output load, improving system−level efficiency over the entire load range. There are two standby functions available to reduce the input power under very light load conditions. The first is an auto−burst mode operation that is internally triggered by periodic sensing, and the other is a manual standby mode, which is executed by clamping the secondary output. In general applications, the manual standby mode reduces the input power further compared to the auto−burst mode. The soft−start function minimizes surge voltage and reduces power stress to the MOSFET and to the secondary rectifying diodes during the start−up sequence. Various protections such as overvoltage, overload, overcurrent, maximum on−time protections and avalanche−energy−guaranteed MOSFET secure good system−level reliability. Features: D Quasi−Resonant Topology IC ⇒ Low EMI Noise and Soft Switching D Bottom−Skip Operation ⇒ Improved System Efficiency Over the Entire Output Load by Avoiding Increase of Switching Frequency D Standby Burst Mode Operation ⇒ Lowers Input Power at Very Light Output Load Conditions D Avalanche−Guaranteed MOSFET ⇒ Improves System−Level Reliability and Does Not Require VDSS derating D 500V / 0.57Ω, 160W (120VAC Input) D Various Protections ⇒ Improved System−Level Reliability S Pulse−By−Pulse Drain Overcurrent Limiting S Overvoltage Protection (Bias Winding Voltage Sensing), with Latch S Overload Protection with Latch S Maximum On−Time Limit Applications: D Set Top Box D LCD PC Monitor, LCD TV D Printer, Scanner D SMPS Power Supplies Absolute Maximum Ratings: (TA = +25°C, Note 1 unless otherwise specified) Drain Current (Single Pulse, Pin1−Pin3), IDpeak . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20A Maximum Switching Current (TA = −20° to +125°C, Pin1−Pin3, Note 2), IDmax . . . . . . . . . . . . . 20A Single Pulse Avalanche Energy, ESA (Single Pulse, VDD = 99V, L = 20mH, ILpeak = 5.8A, Pin1−Pin3) . . . . . . . . . . . . . . . . . 380mJ Input Voltage for Controller [MIC] (Pin4−Pin3), VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35V SS/OLP Terminal Inflow Current (Pin6−Pin3), VSSOLP . . . . . . . . . . . . . . . . . . . . . . . . . . . . −0.5 to 6.0V FB Terminal Inflow Current (Pin6−Pin3), IFB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10mA FB Terminal Voltage (IFB within the limits of IFB, Pin6−Pin3), VFB . . . . . . . . . . . . . . . . . . −0.5 to 9.0V OCP/BD Terminal Voltage (Pin7−Pin3), VOCPBD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −1.5 to 5.0V MOSFET Power Dissipation (Pin1−Pin3), PD1 With infinite heatsink . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28.7W Without heatsink . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3W Controller [MIC] Power Dissipation (VCC * ICC, Pin4−Pin3), PD2 . . . . . . . . . . . . . . . . . . . . . . . . . 0.8W Junction Temperature, TJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +150°C Operating Internal Leadframe Temperature range (Refer to TOP), TF . . . . . . . . . . . . −20° to +115°C Operating Ambient Temperature Range, TOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −20° to +115°C Storage Temperature Range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −40° to +125°C Note 1. All performance characteristics given are typical values for circuit or system baseline design only and are at the nominal operating voltage and ambient temperature of +25°C, unless otherwise stated. Note 2. IDmax is the drain current determined by the drive voltage of the IC and the threshold voltage, Vth, of the MOSFET. Electrical Characteristics: Parameter Symbol Terminals Min Typ Max Unit Electrical Characteristics for Controller (MIC) VCC = 20V, TA = +25°C, Note 3 unless otherwise specified Power Supply Start−Up Operation Operation Start Voltage VCC(ON) Pin4 − Pin3 16.3 18.2 19.9 V Operation Stop Voltage VCC(OFF) Pin4 − Pin3 8.8 9.7 10.6 V Circuit Current In Operation ICC(ON) Pin4 − Pin3 − − 6 mA Circuit Current In Non−Operation ICC(OFF) Pin4 − Pin3 − − 100 μA fOSC Pin1 − Pin3 19 22 25 kHz Soft Start Operation Stop Voltage VSSOLP(SS) Pin5 − Pin3 1.1 1.2 1.4 V Soft Start Operation Charging Current ISSOLP(SS) Pin5 − Pin3 −710 −550 −390 μA Oscillation Frequency Normal Operation Bottom-Skip Operation Threshold Voltage 1 VOCPBD(BS1) Pin7 − Pin3 −0.720 −0.665 −0.605 V Bottom-Skip Operation Threshold Voltage 2 VOCPBD(BS2) Pin7 − Pin3 −0.485 −0.435 −0.385 V Overcurrent Detection Threshold Voltage VOCPBD(LIM) Pin7 − Pin3 −0.995 −0.940 −0.895 V IOCPBD Pin7 − Pin3 −250 −100 −40 μA Quasi-Resonant Operation Threshold Voltage 1 VOCPBD(TH1) Pin7 − Pin3 0.28 0.40 0.52 V Quasi-Resonant Operation Threshold Voltage 2 VOCPBD(TH2) Pin7 − Pin3 0.67 0.80 0.93 V OCP/BDOCP/BD Terminal Outflow Current FB Terminal Threshold Voltage FB terminal Inflow Current (Normal Operation) VFB(OFF) Pin6 − Pin3 1.32 1.45 1.58 V IFB(ON) Pin6 − Pin3 600 1000 1400 μA Note 3. Current polarity with respect to the IC: positive current indicates current sink at the terminal named, negative current indicates source at the terminal named. Electrical Characteristics (Cont’d): Parameter Symbol Terminals Min Typ Max Unit Electrical Characteristics (Cont’d) for Controller (MIC) VCC = 20V, TA = +25°C, Note 3 unless otherwise specified Standby Operation Standby Operation Start Voltage VCC(S) Pin4 − Pin3 10.3 11.1 12.7 V Standby Operation Start Voltage Interval VCC(SK) Pin4 − Pin3 1.10 1.35 1.75 V Standby Non−Operation Circuit Current ICC(S) Pin4 − Pin3 − 20 56 μA FB Terminal Inflow Current, Standby Operation IFB(S) Pin6 − Pin3 − 4 14 μA FB Terminal Threshold Voltage, Standby Operation VFB(S) Pin6 − Pin3 0.55 1.10 1.50 V Minimum On Time ION(MIN) Pin1 − Pin3 − 0.75 1.20 μs Maximum On Time ION(MAX) Pin1 − Pin3 27.5 32.5 39.0 μs Protection Operation Overload Protection Operation Threshold Voltage VSSOLP(OLP) Pin5 − Pin3 4.0 4.9 5.8 V Overload Protection Operation Charging Current ISSOLP(OLP) Pin5 − Pin3 −16 −11 −6 μA Overvoltage Protection Operation Voltage VCC(OVP) Pin4 − Pin3 25.5 27.7 29.9 V Latch Circuit Holding Current (Note 4) ICC(H) Pin4 − Pin3 − 45 140 μA Latch Circuit Release Voltage (Note 4) VCC(La.OFF) Pin4 − Pin3 6.0 7.2 8.5 V Electrical Characteristics for MOSFET TA = +25°C unless otherwise specified Drain−to−Source Breakdown Voltage VDSS Pin1 − Pin3 500 − − V Drain Leakage Current IDSS Pin1 − Pin3 − − 300 μA On Resistance RDS(on) Pin1 − Pin3 − − 0.57 Ω Switching Time tf Pin1 − Pin3 − − 400 ns Junction to Internal Frame − − 1.55 °C/W Thermal Resistance RthJA Note 3. Current polarity with respect to the IC: positive current indicates current sink at the terminal named, negative current indicates source at the terminal named. Note 4. Latch circuit refers to operation during Overload Protection or Overvoltage Protection. Electrical Characteristics: (Test Conditions, Note 5) Parameter Test Conditions VCC (V) Operation Start Voltage VCC voltage at which oscillation starts. 0 → 20 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 Oscillation frequency (fOSC = 1 / T). 20 Soft Start Operation Stop Voltage SS/OLP terminal voltage at which ISS/OLP reach ≥−100μA by raising the SS/OLP terminal voltage from 0V gradually. 20 Soft Start Operation Charging Current SS/OLP terminal charging current (SS/OLP terminal voltage = 0V). 20 Bottom-Skip Operation Threshold Voltage 1 Input 1 μs pulse width to OCP/BD terminal twice after V1−3 rises. After that, offset the input waveform gradually from 0V in the minus direction. Measurement 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 Bottom-Skip Operation Threshold Voltage 2 After measuring VOCPBD(BS1), offset the input waveform gradually. Measurement 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. 20 Note 5. Oscillating operation is specified with a rectangular waveform between Pin1 and Pin3. Electrical Characteristics (Cont’d): (Test Conditions, Note 5) Parameter Test Conditions VCC (V) Overcurrent Detection Threshold Voltage OCP/BD terminal voltage at which oscillation stops by lowering the OCP/BD terminal voltage from 0V gradually. 20 Quasi-Resonant Operation Threshold Voltage 1 OCP/BD terminal voltage at which oscillation starts with setting the OCP/BD terminal voltage at 1V, and then lowering the voltage gradually. 20 Quasi-Resonant Operation Threshold Voltage 2 OCP/BD terminal voltage at which oscillation stops by raising the OCP/BD terminal voltage from 0V gradually. 20 FB Terminal Threshold Voltage 20 FB terminal voltage at which oscillation stops by raising the FB terminal voltage from 0V gradually. FB Terminal Inflow Current (Normal Operation) FB terminal inflow current (FB terminal voltage = 1.6V). Standby Operation Start Voltage VCC voltage at which ICC reaches ≥1mA (FB terminal voltage = 1.6V). Standby Operation Start Voltage Interval Specified by VCC(S) − VCC(OFF). Standby Non−Operation Circuit Current Inflow current flowing into power supply terminals prior to oscillation (FB terminal voltage = 1.6V). 20 0 → 15 − 10.2 FB Terminal Inflow Current, Standby Operation FB terminal inflow current (FB terminal voltage = 1.6V). 10.2 FB Terminal Threshold Voltage Standby Operation FB terminal voltage at which oscillation starts by raising the FB terminal voltage from 0V gradually. 15 Minimum On Time Waveform between terminals 1 and 3 at low. 20 Maximum On Time Waveform between terminals 1 nd 3 at low. 20 Overload Protection Operation Threshold Voltage SS/OLP terminal voltage at which oscillation stops. 20 Overload Protection Operation Charging Current SS/OLP terminal charging current (SS/OLP terminal voltage = 2.5V). − Overvoltage Protection Operation Voltage VCC voltage at which oscillation stops. Latch Circuit Holding Current Inflow current at VCC(OFF) − 0.3; after OVP operation. Latch Circuit Release Voltage VCC voltage at which ICC reaches 20μA or lower by decreasing VCC after OVP operation. 0 → 30 VCC(OFF) −0.3 30 → 6 Note 5. Oscillating operation is specified with a rectangular waveform between Pin1 and Pin3. Pin Connection Diagram (Front View) Protection/Bottom 7 Overcurrent Detection (OCP/BD) 6 Feedback (FB) 5 Soft Start/Overload Protection (SS/OLP) 4 VCC 3 Source/GND 2 No Pin 1 Drain .157 (4.0) .165 (4.2) .394 (10.0) .110 (2.8) .311 (7.9) .665 (16.9) 1 3 7 .197 (5.0) .409 (10.4) .213 (5.4) .050 (1.27) .200 (5.08)