SNVS215D April   2003  – November 2015 LM5030

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 High-Voltage Start-Up Regulator
      2. 7.3.2 Error Amplifier
      3. 7.3.3 PWM Comparator
      4. 7.3.4 Current Limit and Current Sense
      5. 7.3.5 Oscillator, Shutdown and Sync Capability
      6. 7.3.6 Slope Compensation
      7. 7.3.7 Soft Start and Shutdown
      8. 7.3.8 OUT1, OUT2, and Time Delay
      9. 7.3.9 Thermal Protection
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 VCC
        2. 8.2.2.2 Current Sense
        3. 8.2.2.3 Shutdown
        4. 8.2.2.4 External Sync
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

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発注情報

8 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.

8.1 Application Information

The LM5030 is a highly integrated PWM controller that contains all of the features necessary for implementing push-pull topology power converters. The device targets DC-DC converter applications with input voltages of up to 100 VDC and output power in the range 15 W to 150 W.

8.2 Typical Application

The schematic in Figure 8 shows an example of a 33-W push-pull converter controlled by a LM5030. The operating input range is 36 V to 75 V, and the output voltage is 3.3 V. The output current capability is 10 A. The converter is configured for input current protection with cycle-by-cycle current limit. An auxiliary winding is used to raise the VCC voltage to reduce the controller power dissipation.

LM5030 20058103.png Figure 8. Typical Application Circuit, 36-V to 75-V IN and 3.3-V, 10-A OUT

8.2.1 Design Requirements

For this design example, use the input parameters listed in Table 1.

Table 1. Design Parameters

PARAMETER MIN NOM MAX UNIT
Input Voltage 36 75 V
Output Voltage 3.3 V
Output Current 0 10 A
Efficiency (Full Load) 82.5%
Efficiency (Half Load) 84.5%
Load Regulation 1%
Line Regulation 0.15%
Output Current Limit 11 A

8.2.2 Detailed Design Procedure

8.2.2.1 VCC

While the LM5030 internally generates a voltage at VCC (7.7 V), the internal regulator is used mainly during the start-up sequence. Once the load current begins flowing through L2, which is both an inductor for the output filter and a transformer, a voltage is generated at the secondary of L2, which powers the VCC pin. When the externally applied voltage exceeds the internal value (7.7 V), the internal regulator shuts off, thereby reducing internal power dissipation in the LM5030. L2 is constructed such that the voltage supplied to VCC ranges from approximately 10.6 V to approximately 11.3 V, depending on the load current (see Figure 9).

LM5030 20089205.gif Figure 9. VCC Voltage vs Load Current

8.2.2.2 Current Sense

Monitoring the input current provides a good indication of the operation of the circuit. If an overload condition should exist at the output (a partial overload or a short circuit), the input current would rise above the nominal value shown in Figure 12. Transformer T2, in conjunction with D3, R9, R12 and C10, provides a voltage to pin 8 on the LM5030 (CS) which is representative of the input current flowing through its primary. The average voltage seen at pin 8 is plotted in Figure 10. If the voltage at the first current sense comparator exceeds 0.5 V, the LM5030 disables its outputs, and the circuit enters a cycle-by-cycle current limit mode. If the second level threshold (0.625 V) is exceeded due to a severe overload and transformer saturation, the LM5030 will disable its outputs and initiate a softstart sequence. However, the very short propagation delay of the cycle-by-cycle current limiter (CS1), the design of the CS filter (R9, R12, and C10), and the conservative design of the output inductor (L2), may prevent the second level current threshold from being realized on this evaluation board.

LM5030 20089206.gif Figure 10. Average Voltage at the CS Pin vs Input Current

8.2.2.3 Shutdown

The Shutdown pad (SD) on the board connects to the SoftStart pin on the LM5030 (pin 10), and permits on/off control of the converter by an external switch. SD should be pulled below 0.45 V, with an open collector or open drain device, to shut down the LM5030 outputs and the VCC regulator. If the voltage at the SD pad is between 1.0 and 1.5 V, a partial-on condition results, which could be disruptive to the system. Therefore, the voltage at the SD pad should transition quickly between its open circuit voltage (4.9 V) and ground.

8.2.2.4 External Sync

Although the LM5030 includes an internal oscillator, its operating frequency can be synchronized to an external signal if desired. The external source frequency must be higher than the internal frequency set with the RT resistor (262 kHz with RT = 20 kΩ). The sync input pulse width must be between 15 and 150 ns, and have an amplitude of 1.5 to 3.0 V at the Sync pad on the board. The pulses are coupled to the LM5030 through a 100-pF capacitor (C16) as specified in the data sheet.

Table 2. Bill of Materials

ITEM PART NUMBER DESCRIPTION VALUE
C 1 C0805C472K5RAC Capacitor, CER, KEMET 4700 p, 50 V
C 2 C0805C103K5RAC Capacitor, CER, KEMET 0.01 µ, 50 V
C 3 C4532X7S0G686M Capacitor, CER, TDK 68 µ, 4 V
C 4 T520D337M006AS4350 Capacitor, TANT, KEMET 330 µ, 6.3 V
C 5 T520D337M006AS4350 Capacitor, TANT, KEMET 330 µ, 6.3 V
C 6 C4532X7R3A103K Capacitor, CER, TDK 0.01 µ, 1000 V
C 7 C3216X7R2A104K Capacitor, CER, TDK 0.1 µ, 100 V
C 8 C4532X7R2A105M Capacitor, CER, TDK 1 µ, 100 V
C 9 C4532X7R2A105M Capacitor, CER, TDK 1 µ, 100 V
C 10 C0805C102K1RAC Capacitor, CER, KEMET 1000 p, 100 V
C 11 C1206C223K5RAC Capacitor, CER, KEMET 0.022 µ, 50 V
C 12 C3216X7R1E105M Capacitor, CER, TDK 1 µ, 25 V
C 13 C3216COG2J221J Capacitor, CER, TDK 220 p, 630 V
C 14 C3216COG2J221J Capacitor, CER, TDK 220 p, 630 V
C 15 C1206C104K5RAC Capacitor, CER, KEMET 0.1 µ, 50 V
C 16 C0805C101J1GAC Capacitor, CER, KEMET 100 p, 100 V
C 17 C0805C101J1GAC Capacitor, CER, KEMET 100 p, 100 V
C 18 C3216X7R1H334K Capacitor, CER, TDK 0.33 µ, 50 µ
D 1 MBRB3030CTL Diode, Schottky, ON
D 2 CMPD2838-NSA Diode, Signal, Central
D 3 CMPD2838-NSA Diode, Signal, Central
D 4 CMPD2838-NSA Diode, Signal, Central
D 5 CMPD2838-NSA Diode, Signal, Central
L 1 MSS6132-103 Input Choke, Coilcraft 10 µH, 1.5 A
L 2 A9785-B Output Choke, Coilcraft 7 µH
R 1 CRCW12061R00F Resistor 1
R 2 CRCW12064990F Resistor 499
R 3 CRCW2512101J Resistor 100, 1 W
R 4 CRCW2512101J Resistor 100, 1 W
R 5 CRCW12064022F Resistor 40.2K
R 6 CRCW120610R0F Resistor 10
R 7 CRCW120610R0F Resistor 10
R 8 CRCW12061002F Resistor 10K
R 9 CRCW120623R7F Resistor 23.7
R 10 CRCW12062002F Resistor 20K
R 11 CRCW120610R0F Resistor 10
R 12 CRCW12063010F Resistor 301
R 13 CRCW120610R0F Resistor 10
R 14 CRCW12061001F Resistor 1K
TX 1 A9784-B POWER XFR, COILCRAFT
TX 2 P8208T CURRENT XFR, Pulse 100:1
U1 1 LM5030 REGULATOR, TI
U2 2 MOCD207M OPTO-COUPLER, QT OPTOELECTRONICS
U3 3 LM3411AM5-3.3 REFERENCE, TI
651-1727010 DUAL TERMINALS, MOUSER 3 per ASSY
X 1 SUD19N20-90 FET, N, 200 V, SILICONIX
X 2 SUD19N20-90 FET, N, 200 V, SILICONIX
LM5030 20089204.gif Figure 11. Representative Waveforms

Table 3. Test Data

VIN IOUT t1 t2 Fs V1 V2 V3 V4 V5 V6 V7 V8 V9 V10
36 V 1.0 A 2.2 µS 5.3 µS 266.7 10.5 V 36 V 72 V 90 V 10 V 6 V –10 V –6 V 10 V 6 V
48 V 10 A 1.9 µS 5.5 µS 270.3 11.5 V 48 V 96 V 130 V 18 V 8 V –18 V –8 V 13 V 8 V
75 V 1.0 A 1.2 µS 6.2 µS 270.3 10.5 V 75 V 150 V 200 V 20 V 13 V –20 V –13 V 20 V 13 V

8.2.3 Application Curves

LM5030 20089202.gif
Figure 12. Input Current vs Load Current and VIN
LM5030 20089203.gif
Figure 13. Efficiency vs Load Current and VIN