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TPL 5510
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

TPL 5510

by roadnc on Mon Aug 12, 2019 4:46 pm

I'm trying to run a small 3v gear motor about 5 sec on and then 300 sec off in a continuous loop. It's powered by a solar charged 3.6v battery. Can the TPL 5510 do this without any additional electronics? I'm a novice and am doing this now with a Chinese PCB I don't really understand. I could possible do this with a LM555, I think. This is for a outdoor consumer product that I'm working on and would appreciate any thoughts. Thanks in advance for any assistance.

roadnc
 
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Joined: Mon Aug 12, 2019 4:33 pm

Re: TPL 5510

by adafruit_support_mike on Tue Aug 13, 2019 3:59 am

No, you'll need some additional hardware.

The TPL5110 wakes up at programmed intervals and connects power to the load when it does. By itself, it stays awake and keeps power connected until 50ms before the next wake-up time, shuts off for 50ms, then wakes up again.

You can make it shut down any time before that by sending the DONE pin high, but that does require an extra circuit.

A 555 would be able to count 5 seconds from the time power is connected, and this circuit will generate the pulse you need:

555-5sec.jpg
555-5sec.jpg (30.44 KiB) Viewed 65 times


The 555 pinout is a little strange, so going top to bottom along the left side, the signal names are:

- GND
- Trigger
- Output
- Reset

and from top to bottom along the right are:

- Vcc
- Discharge
- Threshold
- Control

The Trigger and Threshold pins are the main inputs. If the voltage on Trigger is less than 1/3 Vcc, Output goes high and Discharge doesn't conduct current. If the voltage on Threshold is more than 2/3 Vcc, Output goes low and Discharge opens a low-resistance connection to GND.

In the circuit above, the 10uF capacitor discharges through the 1M resistor when power is disconnected. At the instant power is connected, the voltage across the capacitor will be 0V. The end of the capacitor connected to Vcc will rise to the positive supply voltage, and will pull Trigger and Threshold to the same level (since the voltage across the cap is still 0V).

That will make Output go low and Discharge will connect the 220k resistor to GND. The voltage at the end of the capacitor connected to Trigger and Threshold will discharge toward 0V, and it will take about 5 seconds for that voltage to reach 1/3 Vcc.

When the voltage goes below 1/3 Vcc, Output will go high, generating the signal the TPL5110 needs to shut off.

adafruit_support_mike
 
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Re: TPL 5510

by roadnc on Thu Aug 15, 2019 5:12 pm

Thanks for the information...I think I understand. The top right lead from the 555 (vcc) goes to the 5510 vdd pin, the left output lead goes to the 5510 done pin, and the ground pin goes to ground. My motor would then attach to ground and the 5510 DRV pin. Is that all correct?
Can I vary the 5 second duration by substituting a variable resistor for the 1M resistor. Also, do I need a LM555 instead of a standard 555 because of the 3.6v...not 5v?
Finally, will this added 555 circuit be a power "miser"; I don't have alot of power to spare.
Thanks in advance for your assistance!

roadnc
 
Posts: 2
Joined: Mon Aug 12, 2019 4:33 pm

Re: TPL 5510

by adafruit_support_mike on Fri Aug 16, 2019 9:42 pm

roadnc wrote:The top right lead from the 555 (vcc) goes to the 5510 vdd pin, the left output lead goes to the 5510 done pin, and the ground pin goes to ground. My motor would then attach to ground and the 5510 DRV pin. Is that all correct?

Yes, that's correct.

roadnc wrote:Can I vary the 5 second duration by substituting a variable resistor for the 1M resistor.

You don't need to.. the TPL5110 breakout has a built-in potentiometer that you can adjust to set the timing.

One point to note: the TPL5110 only reads the timing resistance for the first 100ms after you connect power. After that, you can't change the timing until you disconnect and reconnect the power.

roadnc wrote:Also, do I need a LM555 instead of a standard 555 because of the 3.6v...not 5v?

The low-voltage/low-current version of the 555 is generically known as the 7555:

https://www.digikey.com/product-detail/ ... -ND/821488

roadnc wrote:Finally, will this added 555 circuit be a power "miser"; I don't have alot of power to spare.

The current used by the circuit above won't even be a rounding error compared to the current that drives the motor.

The 7555 uses 60uA and the current that charges the capacitor will max out at about 17uA. The combined load will be about 1/12th of 1mA.

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Please be positive and constructive with your questions and comments.