1207A ON Semiconductor, 1207A Datasheet
1207A
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1207A Summary of contents
Page 1
... PWM Current−Mode Controller for Free Running Quasi−Resonant Operation The NCP1207A combines a true current mode modulator and a demagnetization detector to ensure full borderline/critical Conduction Mode in any load/line conditions and minimum drain voltage switching (Quasi−Resonant operation). Due to its inherent skip cycle capability, the controller enters burst mode as soon as the power demand falls below a predetermined level ...
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... The IC ground 5 Drv Driving pulses 6 V Supplies the High−voltage pin NCP1207A + OVP and NCP1207A Demag Figure 1. Typical Application Function The auxiliary FLYBACK signal ensures discontinuous operation and offers a fixed overvoltage detection level of 7.2 V. ...
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... Maximum ratings are those values beyond which device damage can occur. Maximum ratings applied to the device are individual stress limit values (not normal operating conditions) and are not valid simultaneously. If these limits are exceeded, device functional operation is not implied, damage may occur and reliability may be affected. NCP1207A VUVLO 4.5 ms ...
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... Low State (Ipin 1 = −2.0 mA) Demag Propagation Delay Internal Input Capacitance at Vpin 1 = 1.0 V Minimum T (Internal Blanking Delay after T OFF Timeout After Last Demag Transition Pin 1 Internal Impedance 1. Max value NCP1207A (For typical values for min/max values T J Rating Pin ...
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... TEMPERATURE ( C) Figure 5. VCC Increasing Level at which the Current Source Turns−Off versus Temperature − TEMPERATURE ( C) Figure 7. Internal Startup Current Source versus Temperature CC NCP1207A 2.3 2.1 1.9 1.7 1.5 1.3 1 100 125 −25 11.2 10.8 10.4 10 9.6 9.2 8 100 125 −25 Current Source Turns− ...
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... TEMPERATURE ( C) Figure 9. Input Voltage (Vpin1 Decreasing) versus Temperature NCP1207A 1.20 1.15 1.10 1.05 1.00 0.95 0. 100 125 −25 8.0 7.8 7.6 7.4 7.2 7.0 6.8 6.6 6.4 6.2 6.0 − TEMPERATURE ( C) Figure 11. OVP internal Reference Level versus Temperature http://onsemi.com TEMPERATURE ( C) Figure 10. Maximum Internal Current Setpoint ...
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... Overcurrent Protection (OCP): by continuously monitoring the FB line activity, NCP1207A enters burst mode as soon as the power supply undergoes an technology, the overload. The device enters a safe low power operation which prevents from any lethal thermal runaway ...
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... IC consumption plus the above driving current (altered by the driver’s efficiency). Suppose that the IC is supplied from a 350 VDC line. The current flowing through pin direct image of the NCP1207A consumption (neglecting the switching losses of the HV current source equals 2 CC2 dissipated (lost) by the IC is simply: 350 ...
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... The skip level selection is done through a simple resistor inserted between the current sense input and the sense element. Every time the NCP1207A output driver goes low, a 200 mA source forces a current to flow through the sense pin (Figure 15): when the driver is high, the current source is off and the current sense information is normally processed ...
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... ON 2.0 Figure 20. A voltage sample is taken 4.5 ms after When an OVP condition has been detected, the NCP1207A enters a latchoff phase and stops all switching , a re−start delay is created dem operations. The controller stays fully latched in this position and the DSS is still active, keeping the V V/ normal operations ...
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... Several solutions exist to cure this trouble: The first one consists in adding some copper area around the NCP1207A DIP8 footprint. By adding a min pad area C/W. Maximum power then grows up to 730 mW. A resistor R negative spikes at turn−off (see below) b) split the power budget between this resistor and the package ...
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... V 5.3 V DRV INTERNAL FAULT FLAG STARTUP PHASE Soft−Start The NCP1207A features an internal 1 ms soft−start to soften the constraints occurring in the power supply during startup activated during the power on sequence. As soon as V reaches VCC CC OFF increased from nearly zero up to the maximum clamping NCP1207A NCP1207A hosts a dedicated overload detection circuitry ...
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... HV Pin Recommended Protection When the user unplugs a power supply built with a QR controller such as the NCP1207A, two phenomena can appear negative ringing can take place on pin8 due to a resonance between the primary inductance and the bulk capacitor ...
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... GATE 200 Current Sense Pin (200 mV/div) Figure 27. This picture explains how the 200 mA internal offset current creates the skip cycle level. NCP1207A V (200 mV/div) Rsense SKIP The short−circuit protection forces the IC to enter burst in presence of a secondary overload. ...
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... −A− NOTE 2 −T− SEATING PLANE G H NCP1207A PACKAGE DIMENSIONS PDIP−8 N SUFFIX CASE 626−05 ISSUE L 5 −B− 0.13 (0.005 http://onsemi.com 15 NOTES: 1. DIMENSION L TO CENTER OF LEAD WHEN FORMED PARALLEL ...
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... D 0.25 (0.010) M The product described herein (NCP1207A), may be covered by one or more of the following U.S. patents: 6,362,067, 6,385,060, 6,385,061, 6,429,709, 6,587,357, 6,633,193. There may be other patents pending. ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice to any products herein ...