Texas Instruments LM2695EVAL Скачать руководство пользователя страница 10 | Manualshive

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Texas Instruments LM2695EVAL Скачать руководство пользователя страница 10

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PCB Layout

Figure 11. Board Silkscreen

Figure 12. Board Top Layer

Figure 13. Board Bottom Layer (viewed from top)

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AN-1444 LM2695 Evaluation Board

SNVA147A – February 2006 – Revised April 2013

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Copyright © 2006–2013, Texas Instruments Incorporated

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Содержание LM2695EVAL

Страница 1: ...d managing the output ripple as described later in this document The board s specification are Input Voltage 12 V to 30 V Output Voltage 10 V Maximum load current 1 0A Minimum load current 0A Current Limit 1 3A Measured Efficiency 96 3 VIN 12 V IOUT 300 mA Nominal Switching Frequency 380 kHz Size 2 25 in x 0 88 in x 0 47 in Figure 1 Evaluation Board Top Side 2 Theory of Operation Figure 6 shows a ...

Страница 2: ... an ammeter or a current probe It is recommended that the input voltage be increased gradually to 12 V at which time the output voltage should be 10 V If the output voltage is correct with 12 V at VIN then increase the input voltage as desired and proceed with evaluating the circuit 5 Output Ripple Control The LM2695 requires a minimum of 25 mVp p ripple at the FB pin in phase with the swtiching w...

Страница 3: ...3 3 where tON is the maximum on time 2300 ns VIN is the minimum input voltage and ΔV is the desired ripple amplitude at the R6 C9 junction 30 mVp p for this example 4 R6 and C9 are then chosen from standard value components to satisfy the above product For example C9 can be 1000 pF requiring R6 to be 166 kΩ C10 is chosen to be 0 01 µF large compared to C9 The circuit as supplied on this EVB is sho...

Страница 4: ...re 3 Intermediate Ripple Level Configuration Using C8 and R4 R4 is chosen to generate 25 mV 30 mVp p at VOUT1 knowing that the minimum ripple current in this circuit is 50 mAp p at minimum VIN C8 couples that ripple to the FB pin without the attenuation of the feedback resistors C8 s minimum value is calculated from Equation 5 5 where tON max is the maximum on time at minimum VIN and R2 R3 is the ...

Страница 5: ...nce R4 slightly degrades load regulation this alternative may be viable for applications where the load current is relatively constant If this method is used ensure R4 s power rating is appropriate 6 Increasing the Current Limit The current limit threshold is nominally 1 25A with a minimum guaranteed value of 1 0A If at maximum load current the lower peak of the inductor current IPK in Figure 5 ex...

Страница 6: ...re necessary If it exceeds 1 5A R5 must be reduced The upper peak of the inductor current IPK at maximum load current is calculated using Equation 10 10 where IOR max is calculated using Equation 11 11 where L1min is the minimum inductor value based on the manufacturer s tolerance and FS min is the minimum switching frequency 380 kHz 25 285 kHz for this evaluation board If IPK exceeds 2A the induc...

Страница 7: ...ge Value C1 2 Ceramic Capacitor TDK C4532X7R2A225M 1812 2 2 µF 100 V C3 Ceramic Capacitor TDK C2012X7R2A104M 0805 0 1 µF 100 V C4 Ceramic Capacitor TDK C2012X7R1C104M 0805 0 1 µF 16 V C5 6 Ceramic Capacitor TDK C2012X7R1C223M 0805 0 022 µF 16 V C7 Ceramic Capacitor TDK C3225X7R1C226M 1210 22 µF 16 V C8 Unpopulated 0805 C9 Ceramic Capacitor TDK C2012X7R2A102M 0805 1000 pF C10 Ceramic Capacitor TDK ...

Страница 8: ...95 100 EFFICIENCY LOAD CURRENT mA Vin 12V Vin 30V 18V 24V Circuit Performance www ti com 8 Circuit Performance Figure 7 Efficiency vs Load Current Figure 8 Efficiency vs Input Voltage 8 AN 1444 LM2695 Evaluation Board SNVA147A February 2006 Revised April 2013 Submit Documentation Feedback Copyright 2006 2013 Texas Instruments Incorporated ...

Страница 9: ...PLE AT V OUT1 mVp p Load Current 100 mA Option C Option B Options A D 12 www ti com Circuit Performance Figure 9 Output Voltage Ripple Figure 10 Switching Frequency vs Load Current 9 SNVA147A February 2006 Revised April 2013 AN 1444 LM2695 Evaluation Board Submit Documentation Feedback Copyright 2006 2013 Texas Instruments Incorporated ...

Страница 10: ... Board Silkscreen Figure 12 Board Top Layer Figure 13 Board Bottom Layer viewed from top 10 AN 1444 LM2695 Evaluation Board SNVA147A February 2006 Revised April 2013 Submit Documentation Feedback Copyright 2006 2013 Texas Instruments Incorporated ...

Страница 11: ...esponsible for compliance with all legal regulatory and safety related requirements concerning its products and any use of TI components in its applications notwithstanding any applications related information or support that may be provided by TI Buyer represents and agrees that it has all the necessary expertise to create and implement safeguards which anticipate dangerous consequences of failur...

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