ld7578j Leadtrend Technology, ld7578j Datasheet
ld7578j
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ld7578j Summary of contents
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... The device provides functions of low startup current, green-mode power-saving operation, leading-edge blanking of the current sensing and internal slope compensation. Also, the LD7578J features more protections like OLP (Over Load Protection), OVP (Over Voltage Protection), and OTP (Over Temperature Protection) to prevent the circuit being damaged under the abnormal conditions ...
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... Switching Part number Freq. LD7578J GS 65KHz LD7578J GN 65KHz The LD7578J is green packaged. Pin Descriptions PIN NAME Pull this pin lower than 0.95V to shutdown the controller into latch mode until the AC power-on recycles. By connecting a NTC with this pin to ground, it can achieve the 1 (-) LATCH OTP protection function ...
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... Block Diagram Leadtrend Technology Corporation LD7578J-DS-00 March 2009 3 www.leadtrend.com.tw LD7578J ...
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... Stresses beyond the ratings specified in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. Leadtrend Technology Corporation LD7578J-DS-00 March 2009 4 www.leadtrend.com.tw LD7578J 30V -0 ...
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... Leadtrend Technology Corporation LD7578J-DS-00 March 2009 =15.0V) CC CONDITIONS V < UVLO(on), HV=500V CC V > UVLO(off), HV=500V CC V =0V, LD7578J COMP V =3V, LD7578J COMP OLP tripped, LD7578J OVP tripped, LD7578J (-)Latch Pin Tripped LD7578J V =0V COMP COMP pin open V > 1.9 COMP V <1.9 COMP 5 www.leadtrend.com.tw LD7578J MIN TYP ...
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... Leadtrend Technology Corporation LD7578J-DS-00 March 2009 =15.0V) CC CONDITIONS LD7578J LD7578J LD7578J o o -20 C~ =11V-25V) CC (PDR, Power Down Reset) V =15V, Io=20mA CC V =15V, Io=20mA CC Load Capacitance=1000pF Load Capacitance=1000pF LD7578J, 65KHz-Auto recover Latch(PDR) 6 www.leadtrend.com.tw LD7578J MIN TYP MAX UNITS 60.0 65.0 70.0 KHz 22 KHz KHz ± 100 108 1.0 1.05 1.1 ...
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... Temperature (°C) Fig Current Source vs. Temperature (HV=500V, Vcc=0V) 18.0 17.2 16.4 15.6 14.8 14.0 - Temperature (°C) Fig. 3 UVLO (on) vs. Temperature - Temperature (°C) Fig. 5 Frequency vs. Temperature Leadtrend Technology Corporation LD7578J-DS-00 March 2009 0.90 0.89 0.88 0.87 0.86 0.85 80 120 125 -40 12 11.2 10.4 9.6 8 120 125 - ...
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... Vcc (V) Fig. 7 Frequency vs. Vcc - Temperature (°C) Fig. 9 Max Duty vs. Temperature 7.0 6.5 6.0 5.5 5.0 4.5 - Temperature (°C) Fig open loop voltage vs. Temperature COMP Leadtrend Technology Corporation LD7578J-DS-00 March 2009 120 125 -40 6.0 5.5 5.0 4.5 4.0 3.5 ...
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... Vcc voltage is lower than the UVLO(off) threshold thus the current source supply a current of 1mA. Meanwhile, as the Vcc current consume d by the LD7578J is as low as 320μA, most of the HV current is utilized to charge the Vcc capacitor. By using such configuration, the turn-on delay time will be almost the same no matter whether operation condition is under low-line or high-line ...
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... Therefore, A pull-high resistor is embedded internally and thus an external one is not required. Oscillator and Switching Frequency The switching frequency of LD7578J is fixed at 65kHz to provide the optimized operations by considering the EMI performance, thermal treatment, component sizes and transformer design. ...
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... In the LD7578J, the internal slope compensation circuit has been implemented to simplify the external circuit design. On/Off Control The LD7578J can be turned off by pulling COMP pin to lower than 1.2V. The gate output pin of LD7578J will be Leadtrend Technology Corporation LD7578J-DS-00 March 2009 disabled immediately under such condition ...
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... MOSFET until the next UVLO The Vcc OVP function in LD7578J is an auto-recovery type protection. If the OVP condition, usually caused by open feedback loop, is not released, the Vcc will trip the OVP level again and shutdown the output. The Vcc is working in hiccup mode ...
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... UVLO(on) UVLO(off) PDR (8V) Latch Released AC input Voltage AC Off OUT Switching Non-Switching Fig. 19 Leadtrend Technology Corporation LD7578J-DS-00 March 2009 (Recycle) t Switching t Protection Resistor on the Hi-V Path In some other Hi-V processes and designs, there may be a parasitic SCR between HV pin, Vcc and GND. As shown in Fig ...
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... With the Leadtrend’s proprietary Hi-V technology, there is no such parasitic SCR in LD7578J. equivalent circuit of LD7578J’s Hi-V structure. LD7578J has higher capability to sustain negative voltage than similar products. Nevertheless, a 40KΩ resistor is recommended to implement on the Hi-V path as a current limit resistor no matter what negative voltage is present in any situation ...
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... Reference Application Circuit --- 10W (5V/2A) Adapter Pin < 0.15W when Pout = 0W & Vin = 264Vac Schematic Leadtrend Technology Corporation LD7578J-DS-00 March 2009 15 www.leadtrend.com.tw LD7578J ...
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... R53 2.49KΩ, 0805, 1% R54 100Ω, 0805 R55 1KΩ, 0805 R56A 2.7KΩ, 1206 R56B N/A NTC1 5Ω, 3A FL1 20mH T1 EI-22 L51 2.7μH Leadtrend Technology Corporation LD7578J-DS-00 March 2009 Original P C51 C52 C54 C55 CX1 CY1 D1A D1B D1C D1D D2 D4 ...
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... Package Information SOP-8 Symbols θ Leadtrend Technology Corporation LD7578J-DS-00 March 2009 Dimensions in Millimeters MIN MAX 4.801 5.004 0.189 3.810 3.988 0.150 1.346 1.753 0.053 0.330 0.508 0.013 1.194 1.346 0.047 0.178 0.229 0.007 0.102 0.254 0.004 5.791 6 ...
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... Important Notice Leadtrend Technology Corp. reserves the right to make changes or corrections to its products at any time without notice. Customers should verify the datasheets are current and complete before placing order. Leadtrend Technology Corporation LD7578J-DS-00 March 2009 Dimension in Millimeters Dimensions in Inches Min Max Min 9 ...
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... Revision History Rev. Date Change Notice 00 03/03/2009 Original Specification Leadtrend Technology Corporation LD7578J-DS-00 March 2009 19 www.leadtrend.com.tw LD7578J ...