Texas Instruments tps61040EVM-002 User Manual Download | Manualshive

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September 2004

PMP EVMs

User’s Guide

SLVU068A

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Summary of Contents for tps61040EVM-002

Page 1: ... September 2004 PMP EVMs User s Guide SLVU068A ...

Page 2: ...tute 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 property of the third party or a license from TI under the patents or other intellectual property of TI Reproduction of information in TI data books or data sheets is permissible only if reproduction is...

Page 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 responsibility to take any and all appropriate precautions with regard to electrostatic discharge EXCEPT TO THE EXTENT OF THE INDEMNITY SET FORTH ABOVE NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR A...

Page 4: ...ide prior to connecting any load to the EVM output If there 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 60 C The EVM is designed to operate properly with certain components above 60 C as long as the input and output ranges are maintained These components include but are ...

Page 5: ...etup and Test Results Chapter 3 Board Layout Chapter 4 Schematic and Bill of Materials Related Documentation From Texas Instruments TPS61040 41 data sheet literature number SLVS413 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 tested for compliance with the limits of computing devices ...

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Page 7: ...Using Enable 2 4 2 2 4 PWM Dimming Using Injected Voltage on FB 2 4 2 3 Setup 2 4 2 4 Start up 2 5 2 5 LED Ripple Current 2 6 2 6 Switching Waveforms 2 7 2 7 Efficiency 2 8 2 8 Analog Dimming With Analog Voltage Data 2 8 2 9 Analog Dimming With PWM Voltage Data 2 9 2 10 PWM Dimming Using Enable Data 2 10 2 11 PWM Dimming Using Injected Voltage on FB Data 2 12 3 Board Layout 3 1 3 1 Board Layout 3 ...

Page 8: ...g Control Voltage 2 9 2 7 Input Current and Output Current With PWM Dimming Using Enable 2 10 2 8 Output Current vs Duty Cycle for PWM Dimming Using Enable 2 11 2 9 Control Voltage and Output Current 2 12 2 10 Output Current vs Duty Cycle 2 13 3 1 Assembly Layer 3 2 3 2 Top Layer Routing 3 2 3 3 Bottom Layer Routing 3 3 1 1 Performance Specification Summary 1 2 2 1 Input Output Connections 2 2 ...

Page 9: ...ion This chapter contains background information for the TPS61040 and support documentation for the TPS61040EVM 002 evaluation module Topic Page 1 1 Background 1 2 1 2 Performance Specification Summary 1 2 Chapter 1 ...

Page 10: ...lable to the user is to apply a PWM signal to the enable pin of the device More information about output voltage and current ratings of TPS61040 41 devices can be found in the data sheet literature number SLVS413 1 2 Performance Specification Summary Table 1 1 provides a summary of the TPS61040EVM 002 performance specifications All specifications are given for an ambient temperature of 25 C Althou...

Page 11: ...driving four white light LEDs Topic Page 2 1 Input Output Connections 2 2 2 2 EVM Operation 2 2 2 3 Setup 2 4 2 4 Start up 2 5 2 5 LED Ripple Current 2 6 2 6 Switching Waveforms 2 7 2 7 Efficiency 2 8 2 8 Analog Dimming With Analog Voltage Data 2 8 2 9 Analog Dimming With PWM Voltage Data 2 9 2 10 PWM Dimming Using Enable Data 2 10 2 11 PWM Dimming Using Injected Voltage on FB Data 2 12 Chapter 2 ...

Page 12: ... accomplished by regulating the voltage across a current sense resistor The EVM does not operate correctly unless a load is placed between J4 LED Anode and J5 LED Cathode With no load the output voltage increases until clamped by the 27 V zener diode shown in the schematic The EVM provides the user with a place to add up to four LEDs D2 through D6 More or fewer than four LEDs may be used but the c...

Page 13: ...M VREF 1 233 V Vadj_min 0 V Vadj_max 3 3 V Iout_min 0 A Iout_max 20 mA and R2 249 kΩ Using these values R3 is calculated to be 148 3 kΩ and R4 is calculated to be 98 4 Ω 2 2 2 Analog Dimming With PWM Voltage The second method for dimming the LEDs is to inject a pulse width modulated PWM voltage for analog dimming With this method an RC filter is used to convert the PWM control voltage into an anal...

Page 14: ...e maximum desired output current The reference designators correspond to the EVM schematic shown in Chapter 4 R4 VREF Imax For an output current of 20 mA R4 61 6 Ω 2 2 4 PWM Dimming Using Injected Voltage on FB The fourth method for dimming the LEDs is to inject a PWM control voltage into the FB pin of the TPS61040 When the control voltage is low the output current is at its maximum programmed val...

Page 15: ...current at turnon Figure 2 1 shows the startup sequence of the EVM when powered from a 4 0 V Li ion battery The top oscilloscope trace is the input current and the bottom trace is the output current Figure 2 1 Start up Waveforms 0 5 ms 100 mA 3 4 0 5 ms 10 mA 0 5 ms 5 mV 0 2 V 0 1 V 10 mV 1 2 3 4 BWL AC x10 DC x10 DC DC 3 DC 60 mA 500 kS s STOPPED ...

Page 16: ...pple with 3 6 V input and the bottom trace shows the ripple with a 4 2 V input The difference in switching frequency between the two traces is expected and is explained in the data sheet Figure 2 2 Output Ripple Current 2 µs 2 mA div M1 1 2 µs 12 4 mV 0 2 V 0 1 V 10 mV 2 3 4 1 BWL DC x10 DC x10 DC DC 1 DC 45 mV 200 MS s STOPPED A 2 µs 2 mA div ...

Page 17: ...e output voltage plus the forward voltage drop of the diode During this time the inductor transfers its stored energy to the load and the output capacitor When the inductor current decays to zero the SW node rings at a frequency determined by the output inductor and the drain capacitance of the internal FET This ringing indicates a discontinuous boost power supply topology and confirms that the in...

Page 18: ...ed to generate a 0 mA to 20 mA output when the control voltage is varied from 3 3 V to 0 V The appropriate component values may be calculated using the equations provided in the Analog Dimming with Analog Voltage section Using the closest standard values available R2 249 kΩ R3 147 kΩ and R4 100 Ω Figure 2 5 shows the linear relationship between the output current and the control voltage injected i...

Page 19: ... be 10 kΩ and 1 µF to adequately filter a 1 kHz control voltage Figure 2 6 shows how the PWM control voltage at the DIM2 pin on J3 is converted into an equivalent analog voltage on the DIM1 pin on J3 The graph of the output current versus the control voltage is identical to Figure 2 5 after the PWM control voltage is converted into its average dc equivalent Figure 2 6 PWM Control Converted to Anal...

Page 20: ...quency set to 100 Hz and 50 duty cycle The top oscilloscope trace is the output current and the bottom trace is the control voltage seen on the EN pin Note the three stage soft start during the first 1 5 ms of each cycle Figure 2 8 shows the output current versus the duty cycle of the control voltage Figure 2 7 Input Current and Output Current With PWM Dimming Using Enable 2 ms 10 mA div 2 ms 62 m...

Page 21: ...PWM Dimming Using Enable Data 2 11 Setup and Test Results Figure 2 8 Output Current vs Duty Cycle for PWM Dimming Using Enable 0 5 10 15 20 25 0 20 40 60 80 100 Duty Cycle Current mA ...

Page 22: ...uration The control voltage is injected into DIM1 on J3 Figure 2 9 shows the control voltage and the output current for a 5 kHz 50 duty cycle control voltage waveform The top oscilloscope trace is the output current and the bottom trace is the control voltage Figure 2 10 shows the output current versus duty cycle for different PWM frequencies The increased current at higher frequencies results fro...

Page 23: ...ming Using Injected Voltage on FB Data 2 13 Setup and Test Results Figure 2 10 Output Current vs Duty Cycle 0 2 4 6 8 10 12 14 16 18 20 0 20 40 60 80 100 100 Hz 1 kHz 5 kHz 10 kHz 20 kHz Duty Cycle Current mA ...

Page 24: ...2 14 This page intentionally left blank ...

Page 25: ...3 1 Board Layout This chapter provides the TPS61040EVM 002 board layout and illustrations Topic Page 3 1 Board Layout 3 2 Chapter 3 ...

Page 26: ...ard layout for the TPS61040EVM 002 PWB The nodes with a high switching frequency are short and are isolated from the noise sensitive feedback circuitry Careful attention is given to the routing of high frequency current loops See the data sheet for specific layout guidelines Figure 3 1 Assembly Layer Figure 3 2 Top Layer Routing ...

Page 27: ...Board Layout 3 3 Board Layout Figure 3 3 Bottom Layer Routing ...

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Page 29: ...4 1 Schematic and Bill of Materials This chapter provides the TPS61040EVM 002 schematic and bill of materials Topic Page 4 1 Schematic 4 2 4 2 Bill of Materials 4 2 Chapter 4 ...

Page 30: ...23 OnSemi MBR0530T1 D2 D3 D4 D5 Unpopulated open 1 D6 Diode Zener 27 V 94 mA 225 mW 5 SOT23 Motorola MMBZ5254BLT1 5 J1 J2 J4 J5 J6 Header 2 pin 100 mil spacing 36 pin strip 0 100 x 2 Sullins PTC36SAAN 1 J3 Header 3 pin 100 mil spacing 36 pin strip 0 100 x 3 Sullins PTC36SAAN 1 JP1 Header 3 pin 100 mil spacing 36 pin strip 0 100 x 3 Sullins PTC36SAAN 1 L1 Inductor SMT 10 µH 0 76 A 0 23 mΩ 0 150 x 0...

Page 31: ...Mouser Electronics Authorized Distributor Click to View Pricing Inventory Delivery Lifecycle Information Texas Instruments TPS61040EVM 002 ...

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