Can this curcuit work to "Dimmer" of the LED's ?
using TPIC6B595 to control the LEDS, all is then controlled from the Microchip PIC16Fxxxx
Led are 1,85v an resistor R3-R6 is 68Ohm
Using 13.2mA pr Line Giving med total Watt of 156mW pr line,


Datasheet for TPIC6B595
Shifting time will be 3 sec interval, but for Dimming lights i will run a 5khz PWM DC 5-95 % i think.

 

Looks good.
The turn-off time is related directly to the gate resistor value.
You may want to check this to ensure it is switching quickly enough.
Most likely it is, but is something you should check.

 

This is the way we dim LED's and control motor speed with a PIC. Just replace the motor with 12V strings of Led's.

 

Looks good.
The turn-off time is related directly to the gate resistor value.
You may want to check this to ensure it is switching quickly enough.
Most likely it is, but is something you should check.

This is the way we dim LED's and control motor speed with a PIC. Just replace the motor with 12V strings of Led's.
View attachment 232896

Not so smart, i need digital control, not with a variabel resistor.

 

Regarding turn off issues. What is the PWM frequency?

 

Not so smart, i need digital control, not with a variabel resistor.

You don’t need the variable resistor. The PIC can provide the digital control.

If you don’t need the pic, all you need is the IRLZ44N and the 47k resistor.

BTW, if you’re controlling leds, you don’t need the diode across the motor.

 

I will have to use the mcu,
Simpel control like i have in my first post. Have to check the resistor, think the pwm will be 5khz, but dont know yet.

 

If you use a MOSFET driver such as the TC4420/29 you can forget all your worries.

 

Nobody makes an LED rated at one voltage. An LED has a range of voltages. Yours is probably red with a voltage range from 1.7V to 2.2V.
If all 6 LEDs are 1.7V then the 68 ohms fed from 12.0V produces a current of 26mA which might destroy the LEDs.
If the LEDs are 2.2V then six of them need 13.2V plus some voltage for the resistor then they will not produce any light.

 

Nobody makes an LED rated at one voltage. An LED has a range of voltages. Yours is probably red with a voltage range from 1.7V to 2.2V.
If all 6 LEDs are 1.7V then the 68 ohms fed from 12.0V produces a current of 26mA which might destroy the LEDs.
If the LEDs are 2.2V then six of them need 13.2V plus some voltage for the resistor then they will not produce any light.

Ok, then nevermind the datasheet ?
If datasheet says 1,85 i will asume 1.8 to 1.9, or else why have datasheet

The TC4420, just connect direct to MCU pinout. ?
INPUT =5V ?
VDD = 12V ?
GND is ground
OUTPUT Is to the LEDs
No resistor between mcu and Device ?

 

Correct.

No resistor on the gate unless your MCU needs it.

The driver is Schmitt trigger so it will clean up any slow transitions.

 

Correct.

No resistor on the gate unless your MCU needs it.

The driver is Schmitt trigger so it will clean up any slow transitions.

Ok then,
I will connect directly, and 6A at 18v is plenty, Do i need Cooling for it, if only using at most 620 mA 12v.??

 

No, I'm sorry...output is to the MOSFET gate.

See post #15

 

Ok, then nevermind the datasheet ?

Whose datasheet do you have? A datasheet from "over there" that is translated wrongly?
Here is my Name Brand datasheet that says some of its LEDs are 1.5V and others are 2.4V with a very wide range of voltages:

 

So in theory the TC4420/29 can drive LEDs directly, I mean the application notes show it driving a motor.

 

The motor speed controller circuit operates at a low frequency that might cause visible flicker on LEDs.
Reduce the 0.1uF capacitor value for a higher frequency with less flicker.

 

No, he wont be using this circuit to drive the LEDs, it was only an example that the driver can do more than just drive a MOSFET.

Driving LEDs would come directly from the MCU.

 

No, he wont be using this circuit to drive the LEDs, it was only an example that the driver can do more than just drive a MOSFET.

Driving LEDs would come directly from the MCU.

What do u mean. I drive up to 170 Leds with the TPIC6B595 that is controlled by MCU, the MCU should also handle the contrast of the LEDs. By a 5v PWM Signal

 

Why do you need a MOSFET? Why aren't you using the G input to the TPIC for the dimmer?

 

Why do you need a MOSFET? Why aren't you using the G input to the TPIC for the dimmer?

Oh, can i use it for that, ?
PWM direct to this point ?