TLC555 improvement or already existing version

Arakel Horov

Hi guys, happy holidays!

I know the "LTC555" has a very low power consumption(250uA max, 1-2mA for the capacitor and resistors). I was wondering is it possible to decrease this by not dumping the capacitor energy when the timer is low, but storing it somehow, perhaps a second capacitor or a coil inside? I don't know what the efficiency will be, is it even possible?

over 5 years ago

0 LeonardEllis over 5 years ago

TI__Guru 71526 points

Hello Arakel,

You stated the LTC555 as the device, but TI does not have such a device. You also stated it was a timer, so I am assuming you meant to say TLC555, is that correct? Please verify the device part number.

Regards,

~Leonard

0 Arakel Horov over 5 years ago in reply to LeonardEllis

Prodigy 90 points

Sorry about that, its "TLC555", datasheet..

0 Ron Michallick over 5 years ago in reply to Arakel Horov

TI__Guru**** 165036 points

Hello Arakel,

I am not aware of a practical way to regain the capacitor charge.

Does the timing resistor current need to be 1-2mA? "Resistors" is plural so I suspect circuit is the a-stable setup. What is the desired output frequency and duty cycle?

0 Arakel Horov over 5 years ago in reply to Ron Michallick

Prodigy 90 points

Thank you for the replies.

Yes its the a-stable circuit.

The need is less than 1mA. total consumption as it will be working on a battery. The timer will be used to start the electronics with F= 48Hz, T=20mS, DutyCycle=67% ON.

0 Ron Michallick over 5 years ago in reply to Arakel Horov

TI__Guru**** 165036 points

Arakel,

Here are two (of many) options with low timing current.

RA = RB = 1M ohm, C =10nF C0G/NP0

RA = RB = 100k ohm, C =100nF

0 Arakel Horov over 5 years ago in reply to Ron Michallick

Prodigy 90 points

1MOhm seems like too much, give the maximum current consumption of 250uA. Will it be ok?

0 Ron Michallick over 5 years ago in reply to Arakel Horov

TI__Guru**** 165036 points

Arakel,

Current is the reciprocal of resistance , so high resistance is less current flow.

Simulation Schematic

Simulation waveforms

The timing current is below 10uA making it an insignificant current draw.

Note, that the first 1st high pulse is longer than rest that are 48Hz, 67% duty cycle.

Power management

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TLC555 improvement or already existing version