Designing a boost converter

Thread Starter

shibin_varghese

Joined Jan 14, 2019
73
View attachment 200582
Hi friends,
I have a doubt.
In the diagram above, the boost converter is used to power a GSM module that operates in 3.6V.
TPS610995DRVT
has a fixed output of 3.6V and VBAT is a primary battery of 3.6V and can be enabled whenever required.
The purpose of the boost converter is that the GSM module will operate only on the range of 3.4V to 3.8V, so when the battery voltage is below 3.4V, the device will become useless.
The controller is driven directly from the battery.
When the boost converter is enabled it may take more current from the battery and may cause the battery voltage to drop below a certain level which ma lead to reset the controller.
So can I connect the output of the boost converter to any one of the VCC pins of the controller as an alternative source of power?
But the problem I am challenging is that all the VCC pin of the controller are connected internally. So when I connect any one VCC pin to the output of boost converter and all other VCC pin to the battery are conclusively connected to the battery itself (simply saying the input and output of the boost converter is connected to the battery)
How can I solve this problem?
 

ci139

Joined Jul 11, 2016
1,696
the http://www.ti.com/lit/ds/symlink/tps61099.pdf does not specify the particular pin functions/inter-dependencies (in detail)
so by the -- Figure17. FunctionalBlockDiagram -- it would assume you can "isolate" the p5 p6 . . . at your own "risk" ... the "8.3.8 Down Mode Regulationand Pass-Through Operation" likely hints you don't want to try this out
 

Thread Starter

shibin_varghese

Joined Jan 14, 2019
73
the http://www.ti.com/lit/ds/symlink/tps61099.pdf does not specify the particular pin functions/inter-dependencies (in detail)
so by the -- Figure17. FunctionalBlockDiagram -- it would assume you can "isolate" the p5 p6 . . . at your own "risk" ... the "8.3.8 Down Mode Regulation and Pass-Through Operation" likely hints you don't want to try this out
Thank you for your reply.
My boost circuit is working fine.
My doubt is can I connect the output of the boost converter to any one of the VCC pins of the controller as an alternative source of power and all other VCC pins of the controller to the battery even though all VCC pins are connected internally?.
 

Alec_t

Joined Sep 17, 2013
11,744
can I connect the output of the boost converter to any one of the VCC pins of the controller as an alternative source of power and all other VCC pins of the controller to the battery even though all VCC pins are connected internally?
No, since (if I understand you correctly) that shorts the input and output of the boost converter.
 

Thread Starter

shibin_varghese

Joined Jan 14, 2019
73
No, since (if I understand you correctly) that shorts the input and output of the boost converter.
Thank you for your reply.
I am attaching some parts of a datasheet of a GSM module herewith.
In the figure, Pin 51 is connected to the output of the boost converter and the rest of the VCC pin (52&53) are connected to the battery directly.
The datasheet says all the three VCC pins are connected internally.
How can it be solved?.
 

Attachments

ci139

Joined Jul 11, 2016
1,696

Thread Starter

shibin_varghese

Joined Jan 14, 2019
73
https://www.u-blox.com/sites/default/files/SARA-R4_DataSheet_(UBX-16024152).pdf (Pg.-19)
51 VCC - SARA-R412M : supply input for internal BB PMU
52
VCC - SARA-R412M : supply input for internal RF PA ← i guess these require higher amperage 200mA up to 2A
53 VCC - SARA-R412M : supply input for internal RF PA ← the voltage can be as low as 3 ... 3.2V requires less than half-empty Li-Ion 3.7V cell
?? Call/mail Product support https://portal.u-blox.com/s/
But they are connected internally.
 
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