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TPS65950 Power Dissipation

Suresh Samynathan
Intellectual 360 points
Other Parts Discussed in Thread: TPS65950, OMAP3503

Hi,

This is related to power dissipation of the TPS65950 when powering OMAP3503 processor.

 

In our application, the TPS65950 is powered from USB and the input to the TPS65950 is 4.5V maximum (LDO is used to drop the voltage). The USB interface is used in device mode and charge pump not used. Audio interface is not used; VINTANA2 power is calculated except the external audio interface loads since the exact internal power consumption detail is not available. The VDAC, VMMC1, VMMC1A and VSIM of the OMAP3503 processor is not used.

 

The worst case power analysis is as below considering the tolerances in the power supply

 

 

OMAP3503

TPS65950

 

Power Supply Voltage (max)

Current (max)

 Power Consumption (max)

Power Supply Voltage (max)

Current (max)

 Power Consumption (max)

 Power Loss (max)

 

(V)

(mA)

(mW)

(V)

(mA)

(mW)

(mW)

VDD1(vdd_mpu) - Processor Logic Supply

1.404

768.620

1079.14

4.500

327.01

1438.857

359.714

VDD2(vdd_core) - Core Logic Suply

1.196

264.790

316.689

4.500

88.313

388.575

71.886

vdds_wkup_bg - Bandgap, wakeup + LDO, EMU off

1.872

6.000

11.232

4.500

153.66

676.122

101.418

vdds_sram - SRAM LDOs

1.872

41.000

76.752

vdds - Supply Voltage for I/O macros (All excluding SDRC+GPMC)

1.872

63.000

117.936

vdds_mem - Supply Voltage for memory I/O macros (SDRC+GPMC)

1.872

37.000

69.264

PoP Memory

1.872

160.000

299.520

vdds_dpll_per - Periphals DPLLs Power Supply

1.854

15.000

27.810

4.500

40.110

180.495

106.335

vdds_dpll_dll - Supply Voltage for DPLL I/Os

1.854

25.000

46.350

vdda_dac

0.000

0.000

0.000

0.000

0.000

0.000

0.000

vdds_mmc1 and vdds_mmc1a

0.000

0.000

0.000

0.000

0.000

0.000

0.000

VINTAN1

-

-

-

4.500

50.000

225.000

225.000

VINTAN2

-

-

-

4.500

144.60

650.700

650.700

VINTDIG

-

-

-

4.500

100.00

450.000

450.000

VRRTC

-

-

-

4.500

30.000

135.000

135.000

VUSB1V5

-

-

-

4.500

24.000

108.000

108.000

VUSB1V8

-

-

-

4.500

25.000

112.500

112.500

VUSB3V1

-

-

-

4.500

8.500

38.250

38.250

Total Power Loss

 

 

2044.69

 

 

 

2358.804

 

 

 

 

 

 

 

 

Thermal Resistance (°C/W)

 

 

24.46

 

 

 

38.40

Ambient Temperature (°C)

 

 

40.00

 

 

 

40.00

Junction Temperature (°C)

 

 

90.01

 

 

 

130.58


The TPS65950 junction temperature exceeds its absolute maximum junction temperature.

 

  1. Can you please clarify the TPS65950 will really consume the power specifications provided in the datasheet maximum values
  2. How the packages dissipates the worst case power consumption
  • 0
    TI__Prodigy 200 points

    Hi Suresh,

    Do you have a battery in your system?

    Iif not, Why do not you use the Charger to regulate the Power for your system.

    You will save one LDO.

    Of course, if AUDIO and some other function are not used, you need to re-calculate your max power consumption.

    Example: VINTANA2 will be close to 0.

    Regards,

    David

  • 0 in reply to DavidC
    Intellectual 360 points

    Hi David,

    We have battery in our system and our system should support both the USB power and Battery Power.

    VINTANA2:

    We have already raised the clarfication on the VINTANA2 and TI informed they will not be able to give the data. In our case, we are not using the Audio subchip. Since the approximate current consyumption is not available, we have taken the current other than external audio load. Please refer the below query.

    http://community.ti.com/forums/p/4004/15065.aspx#15065

    Can you tell approximately what will be the power consumption if the AUDIO is not used.

  • 0 in reply to Suresh Samynathan
    TI__Prodigy 200 points

    When AUDIO not used,

    you will be in the range of 1ma.

    Main other block using this resource is MADC.

    Regards,

    David

  • 0 in reply to DavidC
    Intellectual 360 points

    The VINTANA2 powers the analog sections of the Audio Subchip, USB Subchip and Auxillary Subchip (Section 6.3 in TRM). The section 6.4.2.18 in TRM specifies analog sections of the MADC and BCI also supplied by VINTANA2.

    1. The 1mA current specified for VINTANA2 includes all the analog subchips except Audio. Please confirm.

    2. The internal LDOs VINTANA1, VINTDIG and VRRTC maximum current capabilities are given in the datasheet, but the estimated maximum actual current consumption is not provided. This also leads to more power dissipation. Please clarify

  • 0 in reply to Suresh Samynathan
    TI__Prodigy 200 points

    VINDTDIG will be i< 50ma.

    VINTANA1 will be < 20ma.

    VRRTC will be < 5ma

     

    hope it is helping.

     

    Regards,

    David