TPS63001: Drawing more current

harish babu43

Part Number: TPS63001
Other Parts Discussed in Thread: TPS63000

Hi TI,

I am working on LoRaWAN which is a Low Power Wide Area Network (LPWAN) specification intended for wireless battery operated “Things”. LoRaWAN targets key requirements of internet of things such as secure bidirectional communication.

I am using a SIP MOdule the G76S which integrates ARM Cortex®-M0+ (32-bit RISC core operating at a 32MHz frequency) MCU with LoRaTM modulation that provides ultra-long range spread spectrum communication and high interference immunity whilst minimizing current consumption.

I am using TPS63001 Buck Boost, and Battery

Battery:

1. SYSTEM: LITHIUM-THIONYL CHLORIDE, NON-RECHARGABLE
2. NOMINAL VOLTAGE: 3.6V.
3. NOMINAL CAPACITY: 4000 mAh @1mA TO 2.0V @20 C
4. MAXIMUM DISCHARGE: 400mA CONTINUOUS
5. PULSE CAPABILITY: UPTO 800mA

The SIP module G76S is drawing 10uA in the sleep mode, 9mA in stand by mode and 49mA to 127mA in transmitting mode.

With Battery is connected to the input of TPS63001 and the output of TPS63001 is connected to input to the SIP module G76S.

With SIP module G76S In the sleep mode when i measure the current at the input section of TPS63001 the input section is drawing 4mA.

When i bypass TPS63001 and connect battery directly to the input of the SIP module G76S and the SIP module G76S in the sleep mode it is drawing 10uA.

Why TPS63001 is drawing 4MA otherwise which should be drawing in micro amps

I am attaching schematic and layout

Can any one please review my schematic and suggest any changes

over 8 years ago

0 Sabrina over 8 years ago

TI__Expert 8420 points

HI Harish,

this is normal behavior, the TPS63001 is configured in forced PWM mode, means power save mode is disabled (PS/SYNC is high). The no load current of this device in forced PWM mode is in the range of 4mA.
Could you try to connect PS/SYNC to ground and measure again?

0 harish babu43 over 8 years ago in reply to Sabrina

Prodigy 90 points

Hi Sabrina,
Thanks for your reply, i connected PS/SYNC to ground and again measured the input current. I am getting 100 to 150 uA.
For my application can i keep the PS/SYNC pin always grounded.

0 Sabrina over 8 years ago in reply to harish babu43

TI__Expert 8420 points

Yes if the output voltage performance meets your requirements I would recommend to keep PS/SYNC pin tied to ground for this battery powered application where efficiency is important

0 harish babu43 over 8 years ago in reply to Sabrina

Prodigy 90 points

Ok we will implement the same. Other than grounding the PS/SYNC pin which are the other places where we can still optimize the current from 100 to 150 uA to below 100uA. Can you please suggest. Will provide any input from my side.

0 Sabrina over 8 years ago in reply to harish babu43

TI__Expert 8420 points

This is how the converter is designed, its efficiency doesn't allow a lower current consumption.

0 harish babu43 over 8 years ago in reply to Sabrina

Prodigy 90 points

Can you please help us in reviewing our Schematic and layout of TPS63001

0 harish babu43 over 8 years ago in reply to harish babu43

Prodigy 90 points

My VIN is 3.6VDC and VOUT will be constant 3.3VDC.
What happens when VIN 3.6VDC decreases below 3.3V DC, that is between 3.3VDC to 2VDC.
Does the IC will be in power save mode ?.

0 Sabrina over 8 years ago in reply to harish babu43

TI__Expert 8420 points

As shown on on the efficiency curves , when set in PFM. The transition is automatic between PFM and PWM and this depends on the output current actually for all conditions. At light loads the device would be in power save mode and high load in PWM mode. Fig.3 of the datasheet gives you a good idea of how the device efficiency for Vout=3.3V for different input voltages over the load current.

0 harish babu43 over 8 years ago in reply to Sabrina

Prodigy 90 points

Can you please help us in reviewing our Schematic and layout of TPS63001

0 Sabrina over 8 years ago in reply to harish babu43

TI__Expert 8420 points

The schematic seems to follows the datasheet recommendations, but on this version of the schematic , PS/SYNC is connected to VINA which is connected to VIN, if you want to operate the device in power save mode please tie it to ground.

The components placement on the board for the TPS63000 is ok, could you share the layout (with traces, planes, vias...etc)?

0 harish babu43 over 8 years ago in reply to Sabrina

Prodigy 90 points

Please find the attached layout file which is in .brd format.DIGITAL_INTERFACE_CARD_20180205_1.brd

0 Sabrina over 8 years ago in reply to harish babu43

TI__Expert 8420 points

HI Harish
the layout looks fine for me, it follows the datasheet recommendation.

0 harish babu43 over 8 years ago in reply to Sabrina

Prodigy 90 points

When set in PFM. The transition is automatic between PFM and PWM and this depends on the output current actually for all conditions.
When my battery voltage is at 2.5VDC and my main MCU is in sleep mode the MCU is consuming 5UA.

At 2.5VDC battery voltage what will be the state of TPS63001 weather it will be in PFM or in PWM mode. My constant output voltage should be 3.3VDC
when in transmission mode my MCU consumes 90 MA.

0 Sabrina over 8 years ago in reply to harish babu43

TI__Expert 8420 points

When the MCU is in sleep mode, the device is expected operate in PFM mode, when the MCU is transmitting the device may already be in PWM. 90mA is in the region where the device could automatically transit between PFM and PWM. Did you test it by monitoring the switch node of the TPS63000?

0 Sabrina over 8 years ago in reply to Sabrina

TI__Expert 8420 points

HI Harish,

I am closing this thread as the initial problem posted is solved. If you have any other concern please create a new thread.

0 harish babu43 over 8 years ago in reply to Sabrina

Prodigy 90 points

Ok Thank you very much for your help

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TPS63001: Drawing more current