Texas Instruments TPS54973EVM-017 Скачать руководство пользователя страница 14 | Manualshive

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Texas Instruments TPS54973EVM-017 Скачать руководство пользователя страница 14

Modifications

1-6

connector terminals, while leaving J3 open. Headers J5 and J6 are provided
to select two, three, or four series diodes. Install a jumper across the header
to bypass the adjacent diode. Care must be taken to use the correct number
of diodes for the application. Under no circumstances can the output voltage
be allowed to precharge to a level higher than the preset output voltage. If this
condition occurs during startup, the TPS54973 device does not begin
switching. If a voltage transient on the precharge voltage source causes the
series diodes to conduct, current may be sunk through the low side FET in the
device, possibly damaging the device. The actual voltage drop across the
diodes during startup depends on the initial load condition of the circuit as well
as the ambient temperature.

1.3.5

Input Capacitor

An onboard electrolytic input capacitor may be added at C1.

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Содержание TPS54973EVM-017

Страница 1: ...E September 2003 PMP Systems Power User s Guide SLVU091...

Страница 2: ...itute a license from TI to use such products or services or a warranty or endorsement thereof Use of such information may require a license from a third party under the patents or other intellectual p...

Страница 3: ...handling or use of the goods Please be aware that the products received may not be regulatory compliant or agency certified FCC UL CE etc Due to the open construction of the product it is the user s r...

Страница 4: ...ere is uncertainty as to the load specification please contact a TI field representative During normal operation some circuit components may have case temperatures greater than 55 C The EVM is designe...

Страница 5: ...hapter 4 Schematic and Bill of Materials FCC Warning This equipment is intended for use in a laboratory test environment only It gen erates uses and can radiate radio frequency energy and has not been...

Страница 6: ...iv...

Страница 7: ...erations 1 5 1 3 5 Input Capacitor 1 6 2 Test Setup and Results 2 1 2 1 Input Output Connections 2 2 2 2 Efficiency 2 4 2 3 Power Dissipation 2 5 2 4 Output Voltage Regulation 2 6 2 5 Load Transients...

Страница 8: ...eform TPS54973 With No Precharge 2 10 2 12 Measured Start Up Waveform Two Diode Precharge 2 11 2 13 Measured Start Up Waveform Three Diode Precharge 2 11 2 14 Measured Start Up Waveform Four Diode Pre...

Страница 9: ...4973 as well as support documentation for the TPS54973EVM 017 evaluation module HPA0017 The TPS54973EVM 017 performance specifications are given as well as modifications Topic Page 1 1 Background 1 2...

Страница 10: ...ncorporated inside the TPS54973 package This eliminates the need for external MOSFETs and their associated drivers The low drain to source on resistance of the MOSFETs provides the TPS54973 high effic...

Страница 11: ...seful operating range of the TPS54973 device Table 1 2 TPS54973EVM 017 Performance Specification Summary Parameters Test Conditions Min Typ Max Units Input voltage range 3 0 3 3 4 0 V Output voltage s...

Страница 12: ...1 R2 10 kW 0 891 V V O 0 891 V Table 1 3 Output Voltage Programming Output Voltage V R2 Value kW 0 9 1000 1 2 28 7 1 5 14 7 1 8 9 76 2 5 5 49 The minimum output voltage is limited by the minimum cont...

Страница 13: ...e output for a wide variety of output filter component values it is always a good idea to verify any changes to the output filter or compensation network 1 3 4 Precharge Considerations The primary int...

Страница 14: ...e to a level higher than the preset output voltage If this condition occurs during startup the TPS54973 device does not begin switching If a voltage transient on the precharge voltage source causes th...

Страница 15: ...3EVM 017 and covers efficiency output voltage regulation load transients loop response output ripple input ripple and startup Topic Page 2 1 Input Output Connections 2 2 2 2 Efficiency 2 4 2 3 Power D...

Страница 16: ...probe to monitor the output voltage The TPS54973 is intended to be used as a point of load regulator In typical applications it is usually located close to the input voltage source When using the TPS...

Страница 17: ...onnections 2 3 Test Setup and Results Figure 2 1 Connection Diagram Load 0 9A CH1 Oscilloscope 3 4V 8 A Voltmeter 3 4 V 8 A Optional Input Capacitor Optional Precharge Connection Voltmeter POWER SUPPL...

Страница 18: ...ature of 25 C The efficiency is lower at higher ambient temperatures due to temperature variation in the drain to source resistance of the MOSFETs Efficiency is slightly lower at 700 kHz than at lower...

Страница 19: ...and a 9 A load the junction temperature is approximately 60 C while the case temperature is approximately 55 C The total circuit losses at 25 C are shown in Figure 2 3 Power dissipaton is shown for a...

Страница 20: ...s are shown for an ambient temperature of 25 C Figure 2 4 Load Regulation OUTPUT VOLTAGE vs OUTPUT CURRENT IO Output Current A Output Voltage Change V O 0 5 0 4 0 3 0 2 0 1 0 0 1 0 2 0 3 0 4 0 5 0 1 2...

Страница 21: ...oad Transient Response TPS54973 VO ac 50 mV div IO 2 A div t Time 200 s div 2 6 Loop Characteristics The TPS54973EVM 017 loop response characteristics are shown in Figure 2 7 and Figure 2 8 Gain and p...

Страница 22: ...in Gain dB f Frequency Hz MEASURED LOOP RESPONSE Phase deg 2 7 Output Voltage Ripple The TPS54973EVM 017 output voltage ripple is shown in Figure 2 9 The input voltage is 3 3 V for the TPS54973 Output...

Страница 23: ...Ripple The TPS54973EVM 017 output voltage ripple is shown in Figure 2 10 The input voltage is 3 3 V for the TPS54973 Output current for each device is the rated full load of 9 A Figure 2 10 Input Volt...

Страница 24: ...up with the slow start ramp rate At this point the voltage on the VSENSE pin matches the internal reference and the output continues to ramp up to the final set point value of 1 8 V at the slow start...

Страница 25: ...up and Results Figure 2 12 Measured Start Up Waveform Two Diode Precharge VI 500 mV div t Time 5 ms div VO 500 mV div Figure 2 13 Measured Start Up Waveform Three Diode Precharge VI 500 mV div t Time...

Страница 26: ...s in the previous example when the internal reference exceeds the voltage fed back to the VSENSE pin the output begins to ramp up to its final preset value at the slow start rate It is important to no...

Страница 27: ...3 1 Board Layout This chapter provides a description of the TPS54973EVM 017 board layout and layer illustrations Topic Page 3 1 Layout 3 2 Chapter 3...

Страница 28: ...h ground The bottom layer contains ground and VO copper areas some signal routing and pads for two optional D3 or D4 case size electrolytic capacitors The top and bottom ground traces are connected wi...

Страница 29: ...Layout 3 3 Board Layout Figure 3 2 Internal Layer 2 Figure 3 3 Internal Layer 3...

Страница 30: ...Layout 3 4 Figure 3 4 Bottom Side Layout Figure 3 5 Top Side Assembly...

Страница 31: ...Layout 3 5 Board Layout Figure 3 6 Bottom Layer Assembly...

Страница 32: ...4 1 Schematic and Bill of Materials The TPS54973EVM 017 schematic and bill of materials are presented in this chapter Topic Page 4 1 Schematic 4 2 4 2 Bill of Materials 4 3 Chapter 4...

Страница 33: ...9 8 7 6 5 19 18 17 16 15 R4 0 047 F TP9 C5 C4 1 F R6 71 5 k 10 k TP4 R3 R1 10 k 4 02 k C6 3300 pF C8 1200 pF R5 383 C7 120 pF R2 9 76 k TP10 R7 0 TP2 VOUT TP5 J1 VOUT GND 2 1 TP1 C14 0 1 F C13 22 F C...

Страница 34: ...N 3 Shunt 100 mil black 0 100 3M 929950 00 1 L1 Inductor 0 65 H 12 A 0 340 0 250 Pulse PA0277 1 L2 Open 0 51 0 51 2 R1 R6 Resistor chip 10 0 k 1 16 W 1 603 Std Std 1 R2 Resistor chip 9 76 k 1 16 W 1 6...

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