technical help

Hello Satish,
Thank you for posting.

The TPL5111 Nano Timer is a low power system timer, ideal for power gating in duty cycled or
battery powered applications. Consuming only 35 nA, the TPL5111 can be used to enable and
disable the PWM circuit you desire. I would use this for the 20 minute on function.
www.ti.com/.../tpl5111

The LMC555 timer can produce the square wave you want.
www.ti.com/.../lmc555
I chose this one for lowest quiescent current.
The 555 timers have been around for many years.
There are many variations.
www.ti.com/.../timers-products.page

There is also a dual timer, TLC556, of which one timer could produce the PWM and the other could make the 20 minute off function.

For charging the battery I will assume you have 5V available.
Charging Lithium chemistries is usually done at a 1C rate or less.
C is the mAhr rating of the battery, so a 300mAhr battery would charge at 300mA maximum

BQ21040 is a good place to start.
www.ti.com/.../bq21040
The bq21040 is a highly integrated Li-Ion and Li-Pol linear charger device targeted at space-limited portable applications. The device operates from either a USB port or AC adapter. The high input voltage range with input overvoltage protection supports low cost unregulated adapters.


This overview page for Battery Chargers has tools to assist in selection.
www.ti.com/.../battery-charger-ic-overview.page


Please let me know your thoughts.

Hi Satish,

The TSC file is a TINA spice file.

TI has a spice program called TI TINA.

When you install the program you will see most TI devices in the SPICE MACROS tab, other components.

TLC556 is one of the macros that comes installed with TINA.

Attached are the pdf's of the Astable and Monostable TINA files.

TLC556 astable.pdf

TLC556 monostable.pdf

Does this help?
Have a great weekend.