TLV7031: Ultra low power pulse generator

Hi Christos,

have you read section 8.2.3.2 of datasheet?

Kai

Christos

for additional information, please see our latest cookbook circuit on building relaxation oscillation circuits.  In that document, you will see that R2, R3, and R4 can be adjusted in order to create a duty cycle other than 50%.  A TINA reference circuit is also included in the cookbook to assist you in simulating your circuit.

Chuck

www.ti.com/.../snoa998.pdf 

   

Hi Christos,

if the duty cycle is far away from 50%, I would use the double feedback technique, using one feedback path for the high time and the other for the low time:

When filtering the supply voltages powering the OPAmp and the voltage divider R3 / R4 and when using high quality foil capacitors for C1 and C2, the circuit will be surprisingly precise.

I have used high ohmic feedback resistors to save supply current. R6 is needed to limit the input current.

The output signal can also be inverted by reversing the diode. But the circuit will draw much more supply current then:

Com_Osc_Circuit.TSC

I certainly need not to mention that such a high ohmic circuit needs good shielding against hum and interference.

Kai

No, to be honest, i did not..

Thank you Kai klaas69, the last schematic is exactly what i need to achieve.. only.. i already have made pcbs for the original schematic... i would simply like to adjust the component values to that if possible.. i am not that good with this short of calculations.

Thank you kai klaas69

I might need to order new pcbs after all...

I made the ones i have now according to this and it does work nicely but i cannot adjust the component values to have the output 980-990ms OFF 10-20ms ON