All Questions
Tagged with supercapacitor rtc
10
questions
1
vote
1
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149
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Supercapacitor discharging fast when there is no discharge path present
This question is a continuation of my previous question, but different from that.
I am using a PCA85073A RTC in my design. On some boards, the supercapacitor discharges very fast (5 V to 1.1 V in half ...
- 2,593
0
votes
1
answer
77
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What will happen if I2C pull up voltage became zero
This is a continuation of this question.
In my board RTC I2C lines are pulled up to controller supply voltage and the controller supply voltage will be off when the system is off.
At that time also ...
- 2,593
4
votes
1
answer
1k
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RTC super capacitor is discharging very fast
I am using a PCA85073A RTC in my design. On some boards, the supercapacitor discharges very fast (5V to 1.1V in half an hour.)
This happens when we turn off 5V_uC.
The circuit is given below.
All the ...
- 2,593
4
votes
1
answer
595
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Can a memory backup supercap hold on for more than 2 weeks?
Most RTC chips have a VBATT input for backup power supply; besides a battery, you can use a supercap there, e.g. using the following scheme:
simulate this circuit – Schematic created using ...
- 5,469
1
vote
2
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729
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RTC circuit supercapacitor charge/discharge doubts
This is my current RTC circuit...
Supercapacitor = DXJ-5R5V334U (ELNA)...
DXJ-5R5V334U = 0.33F, 5.5V, ESR = 150 Ohms
Resistor = 150 ohms 0603 100mW 1%
If I consider only the resistor, I have a RC ...
- 657
3
votes
2
answers
2k
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RTC backup by super capacitor estimation issue
I create a RTC backup circuit for a STM32L412CBT6. Circuit work but not as long as I estimate during design.
Here is the schematic (VBKP go directly to STM32 VBAT pin):
SC1 capacity is 0.33F
Here is ...
- 498
3
votes
1
answer
3k
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Minimalistic RTC backup battery charging or a super-capacitor?
I am trying to provide RTC power backup for a 3.3V system that will be running at the very least 8hrs during the work day. As such I only need up to a month of backup, enough to survive over long ...
- 8,476
6
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1
answer
5k
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Coin cell battery recharging circuit for RTC backup power
I am designing a system that contains an RTC to for displaying the date and time on a user interface, as well as log events with time stamps. In this particular case, the system gets powered-on at ...
- 665
3
votes
1
answer
1k
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Supercap for Backup Power (10 hours Backup Time Min.)
I am using atxmega8e5 in a design and also utilizing its Real-Time Counter to act as a Real-Time Clock.
A lot of RT-Clock ICs can use a SuperCap to have backup power incase the device is unplugged or ...
- 5,419
13
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4
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supercap-powered RTC?
I'm designing a ATmega-based microcontroller test board. One of the features I want to include is a Real Time Clock with a Maxim DS1307 IC. Instead of including a traditional coin cell battery backup, ...
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