lm5035mhx National Semiconductor Corporation, lm5035mhx Datasheet
lm5035mhx
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lm5035mhx Summary of contents
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... A current sense input and a programmable timer provide cycle-by- cycle current limit and adjustable hiccup mode overload protection. Simplified Application Diagram © 2006 National Semiconductor Corporation Features n 105V / 2A Half-Bridge Gate Drivers n Synchronous Rectifier Control Outputs with Programmable Delays n High Voltage (105V) Start-up Regulator n Voltage mode Control with Line Feed-Forward and Volt • ...
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Connection Diagrams www.national.com Top View 20177502 20-Lead TSSOP EP Top View 20177503 LLP-24 Package 2 ...
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... Ordering Information Order Number Package Type LM5035MH TSSOP-20EP LM5035MHX TSSOP-20EP LM5035SQ LLP-24 LM5035SQX LLP-24 Pin Descriptions TSSOP LLP PIN PIN Name 1 23 RAMP Modulator ramp signal 2 24 UVLO Line Under-Voltage Lockout 3 2 OVP Line Over-Voltage Protection 4 3 COMP Input to the Pulse Width ...
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Pin Descriptions (Continued) TSSOP LLP PIN PIN Name 10 9 RES Restart Timer Boost voltage for the HO driver Switch node High side gate drive output Low side ...
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Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. VIN to GND HS to GND HB to GND VCC to GND CS, RT, DLY to ...
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Electrical Characteristics type apply over full Operating Junction Temperature range 27.4kΩ 3V unless otherwise stated. See (Note 2) and (Note 3). (Continued) DLY UVLO OVP Symbol Parameter Soft-Start (SS Pin) I Charging ...
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Electrical Characteristics type apply over full Operating Junction Temperature range 27.4kΩ 3V unless otherwise stated. See (Note 2) and (Note 3). (Continued) DLY UVLO OVP Symbol Parameter Thermal Shutdown T Shutdown temperature ...
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Typical Performance Characteristics V and VCC REF REF REF Oscillator Frequency vs Temperature www.national.com VIN 20177505 20177507 Soft-Start & Stop Current vs Temperature 20177509 VCC VCC 20177506 Frequency vs RT ...
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Typical Performance Characteristics Effective Comp Input Impedance SR "T1" Parameter vs Temperature (Continued) 20177511 SR "T2" Parameter vs Temperature 20177513 Deadtime DLY 20177512 20177514 www.national.com ...
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Block Diagram www.national.com FIGURE 1. 10 20177504 ...
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Functional Description The LM5035 PWM controller contains all of the features necessary to implement half-bridge voltage-mode controlled power converters. The LM5035 provides two gate driver outputs to directly drive the primary side power MOSFETs and two signal level outputs to ...
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Cycle-by-Cycle Current Limit The CS pin is driven by a signal representative of the trans- former primary current. If the voltage sensed at CS pin exceeds 0.25V, the current sense comparator terminates the output driver pulse. If ...
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Overload Protection Timer (Continued) FIGURE 2. Current Limit Restart Circuit FIGURE 3. Current Limit Restart Timing 13 20177515 20177516 www.national.com ...
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Overload Protection Timer Soft-Start The soft-start circuit allows the regulator to gradually reach a steady state operating point, thereby reducing start-up stresses and current surges. When bias is supplied to the LM5035, the SS pin capacitor is discharged by an ...
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Feed-Forward Ramp and Volt • Second Clamp (Continued) does not exceed 2.5V before the end of the clock period, then the internal clock will enable the discharge MOSFET to reset capacitor proper selection of R and ...
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Gate Driver Outputs (HO & LO) Synchronous Rectifier Control Outputs (SR1 & SR2) Synchronous rectification (SR) of the transformer secondary provides higher efficiency, especially for low output voltage converters. The reduction of rectifier forward voltage drop (0.5V - 1.5V) to ...
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Applications Information The following information is intended to provide guidelines for the power supply designer using the LM5035. VIN The voltage applied to the VIN pin, which may be the same as the system voltage applied to the power transformer’s ...
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Applications Information FIGURE 8. Current Sense Using Current Sense Transformer FIGURE 9. Current Sense Using Current Sense Resistor (R1) If the current sense resistor method is used, the over-current condition will only be sensed while LO is driving the low-side ...
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Applications Information capacitance. Schottky diodes are also a viable option, par- ticularly for lower input voltage applications, but attention must be paid to leakage currents at high temperatures. The internal gate drivers need a very low impedance path to the ...
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Applications Information The impedance seen looking into the resistor divider from the UVLO and OVP pins determines the hysteresis level. UVLO and OVP enable and disable thresholds are calcu- www.national.com (Continued) FIGURE 10. Basic UVLO Configuration FIGURE 11. Basic Over-Voltage ...
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Applications Information Outputs disabled due to VIN falling below UVLO threshold Outputs enabled due to VIN rising above UVLO threshold Outputs disabled due to VIN rising above OVP threshold Outputs enabled due to VIN falling below OVP threshold The typical ...
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Applications Information then leakage current in the zener diode amplified by the opto-coupler’s gain could falsely trip the protection latch. R1 and Q1 are added reduce the sensitivity to low level currents in the opto-coupler. Using the values of Figure ...
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Applications Information In the case of continuous cycle-by-cycle current limit detec- tion at the CS pin, the time required for C 2.5V hiccup mode threshold is: For example 0.01µF the time t1 is approximately RES 1.14 ms. ...
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Application Circuit Example (Continued) reference, U3 and U5 respectively, provide voltage feedback via opto-coupler U4. Synchronous rectifiers Q4, Q5, Q6 and Q7 minimize rectification losses in the secondary. An auxil- iary winding on transformer T1 provides power to the LM5035 ...
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Physical Dimensions www.national.com inches (millimeters) unless otherwise noted Molded TSSOP-20 NS Package Number MXA20A 24-Lead LLP Package NS Package Number SQA24B 26 ...
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National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications. For the most current product information ...