Voltage regulator for solar panel

Thread Starter

twister007

Joined Feb 29, 2012
81
The problem is that the 4011 doesn't act as a switch. With a slow voltage change it acts as an amplifier and burns out the mosfet. I asked here once before and someone recommended a better gate but when I tried to order it a couple of years ago Durring the IC shortage, it was unavailable. Now I would like to order it again but I can't remember what the number was! Can some help please?0201241619.jpg
 

Reloadron

Joined Jan 15, 2015
7,518
The CD4011 is a CMOS version of a quad NAND gate. I have no idea what you are trying to accomplish with a pot wiper tied to both inputs. As a side note when using a CMOS 4011 if only using a few of the gates make sure any unused inputs are tied to GND or VCC do not leave the unused inputs floating. CMOS gate circuits have input and output signal specifications that are quite different from TTL. For a CMOS gate operating at a power supply voltage of 5 volts, the acceptable input signal voltages range from 0 volts to 1.5 volts for a “low” logic state, and 3.5 volts to 5 volts for a “high” logic state. Your VCC determines the point where there is a state change. Can you please post a complete circuit (schematic)? Less knowing voltages and current demand it's about impossible to answer your question. What exactly are you trying to do?

Ron
 

MisterBill2

Joined Jan 23, 2018
18,535
The TC needed will include a "schmitt trigger function. which means that as the input changes slowly the output will jump from low to high. ALL CMOS devices that do NOT include that mode are unsuitable for on/off control. YOU WILL NOT FIND THAT INFORMATION ON THE CARTOON CHANNEL !!!
Also, "R"is correct in that all CMOS gate inputs must be held either low or high, or they will drift into a linear regions where there is no tellin what will happen.
 

AnalogKid

Joined Aug 1, 2013
11,052
To answer your question, and sticking with CD4000-series CMOS parts that can run on 12 V, the two most common options are:

CD4093 - Quad NAND gate with Schmitt Trigger inputs. This probably is the part you were told about. It is a drop-in replacement for the CD4011 in your schematic.

CD40106 - Hex inverter with Schmitt trigger inputs. Since your application does not need the NAND function, just the Schmitt trigger input, any one of the inverters in this part will work for you.

While it is very bad practice to leave unused inputs floating in any logic family, it is particularly bad for non-Schmitt trigger input CMOS parts. There are two separate internal mechanisms for this. With a Schmitt part, one of those mechanisms is addressed but the other remains. CMOS parts have a near-infinite input impedance, so very small stray electromagnetic fields and noise at an unterminated input can cause the output to change state. For example, if you decide to use the 40106 hex inverter, the five unused input must be tied high or low. The unused outputs can be left unconnected.

More than you ever wanted to know: https://en.wikipedia.org/wiki/Schmitt_trigger

ak
 

Thread Starter

twister007

Joined Feb 29, 2012
81
The CD4011 is a CMOS version of a quad NAND gate. I have no idea what you are trying to accomplish with a pot wiper tied to both inputs. As a side note when using a CMOS 4011 if only using a few of the gates make sure any unused inputs are tied to GND or VCC do not leave the unused inputs floating. CMOS gate circuits have input and output signal specifications that are quite different from TTL. For a CMOS gate operating at a power supply voltage of 5 volts, the acceptable input signal voltages range from 0 volts to 1.5 volts for a “low” logic state, and 3.5 volts to 5 volts for a “high” logic state. Your VCC determines the point where there is a state change. Can you please post a complete circuit (schematic)? Less knowing voltages and current demand it's about impossible to answer your question. What exactly are you trying to do?

Ron
Ok, thanks, I forgot to add + 13v to the top of the pot. I also forgot to add a 20k resistor from gate to source to turn off the mosfet. All unused inputs will be grounded.
Is it illegal to tie the inputs together? I could tie one input to +13 v.
You ask what am I trying to do? Isn't it obvious that it is charging a battery with a solar panel?
 

AnalogKid

Joined Aug 1, 2013
11,052
Unused logic inputs can be tied to a working logic signal as long as they do not overload the signal source. This is not a problem with CMOS components in a low-frequency application like yours. Back in the day, TTL logic parts had "fan-out" limitations; a single output could drive a maximum of 10 inputs. This could be a real problem if you were doing something like gating 12 bits on and off.

ak
 

ThePanMan

Joined Mar 13, 2020
793
This is your drawing made easier to read. I've left off the truth table, we all know how a 2 input NAND gate works.
1706884806768.png
It so happens I use a solar panel to power a 9V device that I only want working during the day. The PV (Photo Voltaic, or solar panel) can provide as much as 19VDC but at low currents. I have that tied to a buck converter that maintains an output of 9.6VDC. This is to replace the 9V battery. Mine is not charging a battery, it's replacing the battery "During The Day Only". Which is what I want.

Your circuit makes no sense. And to answer your question as to what that other chip was, I don't know. I'd recommend a buck converter to drop your voltage to the desired level. In the case of a 12 volt battery, should it be a SLA (Sealed Lead Acid) battery it's nominal voltage would be 12V. It's full charged and resting voltage should be 12.6. It's float (maintained state of charge) voltage should be 13.8V. With an adjustable buck converter you can dial in the right voltage for your battery.

WARNING! Battery chemistry can be critical! If you're using some other type of battery such as a lithium type battery you will need a BMS (Battery Management System). You MUST control the input voltage AND current to a lithium type battery or you could destroy it.

Use of a MOSFET to drop that much voltage at some as yet unknown current (voltage times current equals watts) that FET may be seeing far more than what it's designed to handle. Also, if not properly controlled you can be over charging your battery, which can further complicate matters. I suggest you rethink your approach.
 

ThePanMan

Joined Mar 13, 2020
793
This is one such buck converter I quickly found on Amazon. (click here)
It can convert 24V down to 12V at 10A (120W). Notice how much heat sinking it has. And a buck converter is much more efficient than other means of voltage regulation. But don't forget - - - the type of battery is critical to a successful system.
 

BobTPH

Joined Jun 5, 2013
8,989
Why don’t you explain what your circuit is supposed to do and how you think it would accomplished that. I can guess that it is supposed to charge the battery from a solar panel, but that is not what the title says and not what the circuit will do.
 

ThePanMan

Joined Mar 13, 2020
793
This is one such buck converter I quickly found on Amazon. (click here)
Was just looking at some of the other pictures. The fourth picture down (on the left) shows a battery as a load AND it shows the wiring being backwards. PLEASE DON'T FOLLOW THAT DIAGRAM - IT'S AN ERROR. Still, it does have a 4.4 star rating and over 400 reviews. And no, I didn't look at any reviews. Only wanted to show you a buck converter. There are plenty of other options; lower power for sure. Some higher as well.
 

Thread Starter

twister007

Joined Feb 29, 2012
81
The TC needed will include a "schmitt trigger function. which means that as the input changes slowly the output will jump from low to high. ALL CMOS devices that do NOT include that mode are unsuitable for on/off control. YOU WILL NOT FIND THAT INFORMATION ON THE CARTOON CHANNEL !!!
Also, "R"is correct in that all CMOS gate inputs must be held either low or high, or they will drift into a linear regions where there is no tellin what will happen.
Thanks, I will tie unused inputs to ground.
 

Thread Starter

twister007

Joined Feb 29, 2012
81
To answer your question, and sticking with CD4000-series CMOS parts that can run on 12 V, the two most common options are:

CD4093 - Quad NAND gate with Schmitt Trigger inputs. This probably is the part you were told about. It is a drop-in replacement for the CD4011 in your schematic.

CD40106 - Hex inverter with Schmitt trigger inputs. Since your application does not need the NAND function, just the Schmitt trigger input, any one of the inverters in this part will work for you.

While it is very bad practice to leave unused inputs floating in any logic family, it is particularly bad for non-Schmitt trigger input CMOS parts. There are two separate internal mechanisms for this. With a Schmitt part, one of those mechanisms is addressed but the other remains. CMOS parts have a near-infinite input impedance, so very small stray electromagnetic fields and noise at an unterminated input can cause the output to change state. For example, if you decide to use the 40106 hex inverter, the five unused input must be tied high or low. The unused outputs can be left unconnected.

More than you ever wanted to know: https://en.wikipedia.org/wiki/Schtmitt_trigger

ak
To answer your question, and sticking with CD4000-series CMOS parts that can run on 12 V, the two most common options are:

CD4093 - Quad NAND gate with Schmitt Trigger inputs. This probably is the part you were told about. It is a drop-in replacement for the CD4011 in your schematic.

CD40106 - Hex inverter with Schmitt trigger inputs. Since your application does not need the NAND function, just the Schmitt trigger input, any one of the inverters in this part will work for you.

While it is very bad practice to leave unused inputs floating in any logic family, it is particularly bad for non-Schmitt trigger input CMOS parts. There are two separate internal mechanisms for this. With a Schmitt part, one of those mechanisms is addressed but the other remains. CMOS parts have a near-infinite input impedance, so very small stray electromagnetic fields and noise at an unterminated input can cause the output to change state. For example, if you decide to use the 40106 hex inverter, the five unused input must be tied high or low. The unused outputs can be left unconnected.

More than you ever wanted to know: https://en.wikipedia.org/wiki/Schmitt_trigger

ak
Thanks! It looks like the 4093 Will work perfectly! Plus it only ha .9 V histeris! I made a voltage regulator with the Schmidt trigger, in fact it is hooked up now, but I don't like it because it has a histeris of 1.5 v.
The 4011 works perfectly except for going into an amplifier state instead of a switch state. Even in the amplifier state it maintains the voltage right on the money, but it burns off the excess voltage as heat. I used it for a couple of years and it would have worked ok with forced air cooling. After many cycles the mosfet would finally give up even with the large case as a heat sink.
 

Thread Starter

twister007

Joined Feb 29, 2012
81
This is your drawing made easier to read. I've left off the truth table, we all know how a 2 input NAND gate works.
View attachment 314199
It so happens I use a solar panel to power a 9V device that I only want working during the day. The PV (Photo Voltaic, or solar panel) can provide as much as 19VDC but at low currents. I have that tied to a buck converter that maintains an output of 9.6VDC. This is to replace the 9V battery. Mine is not charging a battery, it's replacing the battery "During The Day Only". Which is what I want.

Your circuit makes no sense. And to answer your question as to what that other chip was, I don't know. I'd recommend a buck converter to drop your voltage to the desired level. In the case of a 12 volt battery, should it be a SLA (Sealed Lead Acid) battery it's nominal voltage would be 12V. It's full charged and resting voltage should be 12.6. It's float (maintained state of charge) voltage should be 13.8V. With an adjustable buck converter you can dial in the right voltage for your battery.

WARNING! Battery chemistry can be critical! If you're using some other type of battery such as a lithium type battery you will need a BMS (Battery Management System). You MUST control the input voltage AND current to a lithium type battery or you could destroy it.

Use of a MOSFET to drop that much voltage at some as yet unknown current (voltage times current equals watts) that FET may be seeing far more than what it's designed to handle. Also, if not properly controlled you can be over charging your battery, which can further complicate matters. I suggest you rethink your approach.
Thanks for turning the foto around! Pardon for the poor foto, my camera lens gets scratched from carrying it in my pocket. I need to change it AGAIN! HA!
The buck converter is a good idea, but will it interfere with am radio? I built a pulse width modulated voltage regulator, and it worked good but it interfered with my am radio and I tried every frequency on the oscillator! It didn't effect my tv at all though.
 

MisterBill2

Joined Jan 23, 2018
18,535
If you want the solar panel to power a device that you only want to operate during the day, WHY IS IT CHARGING A BATTERY?????
And, if you want to charge a battery, why not simply connect the solar cell to the battery?

It may be that the solar cell panel would over charge the battery, so you will need a circuit to disconnect the battery when it becomes fully charged. THAT might be a bit tricky, and you will not do it with a logic gate. . Charge control does not work that way.. There must be something that senses the battery state of charge, and that part of the circuit then tells another part to switch off the charge current.
 

bassbindevil

Joined Jan 23, 2014
828
You know you can buy PWM charge controllers for around ten bucks on ebay? Complete with LCD displays for voltage and status, USB charger outputs, and an optional switched output suitable for lighting applications. Some of them support 3S lithium ion and 4S LFP chemistry as well as lead acid now.

PWM can interfere with AM radio; I've noticed that with a friend's backyard solar system.

But if you only need to run a 9V device when the sun shines, maybe an MC34063 buck converter would be enough. Those can often be found inside car cellphone chargers and USB adapters. Change a resistor or two to get 9V instead of 5V out.
 
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