AS123 | PartQuest™ Explore

The AS123 LED Driver from ACME Semiconductor (fictional) provides fully integrated PWM dimming and a programmable current set-point. This IC is specifically for automotive rear combination (tail/stop) lighting applications. It tightly regulates the desired string current under conditions of widely varying applied DC voltage.The PWM dimming function, which switches the LED on and off at just over 300 Hz, is active when the line input pin is high and the "PWM_disable" pin is low (The AS123 supports current programming using a single external resistor (see r_iset in the schematic). The resistor value can be selected to give the desired LED string current, using the following formula:r_iset = 1.85/i_desired The AS123 is capable of regulating up to 100mA per string continuously. Therefore the value of r_iset should be no less than 18.5 Ohms. The user can change this resistor value and run a new simulation, to see the effect of this change on the LED string current. See a "functional block diagram" schematic model of the ACME AS123 here: https://www.systemvision.com/design/acme-as123-led-driver-schematic-model-------------- End of Example Application Note ------------------If you are a component supplier, this type of "Live Application Note" can help your potential customers better understand the features and benefits of your components.

About text formats

ACME AS123 LED Driver with Dimmer Control - Application Note

MurshidulHakimee
Designer203528

MurshidulHakimee

Member for

5 years 6 months

2

designs

1

groups

Add a bio to your profile to share information about yourself with other SystemVision users.

Description

The AS123 LED Driver from ACME Semiconductor (fictional) provides fully integrated PWM dimming and a programmable current set-point. This IC is specifically for automotive rear combination (tail/stop) lighting applications. It tightly regulates the desired string current under conditions of widely varying applied DC voltage.The PWM dimming function, which switches the LED on and off at just over 300 Hz, is active when the line input pin is high and the "PWM_disable" pin is low (The AS123 supports current programming using a single external resistor (see r_iset in the schematic). The resistor value can be selected to give the desired LED string current, using the following formula:r_iset = 1.85/i_desired The AS123 is capable of regulating up to 100mA per string continuously. Therefore the value of r_iset should be no less than 18.5 Ohms. The user can change this resistor value and run a new simulation, to see the effect of this change on the LED string current. See a "functional block diagram" schematic model of the ACME AS123 here: https://www.systemvision.com/design/acme-as123-led-driver-schematic-model-------------- End of Example Application Note ------------------If you are a component supplier, this type of "Live Application Note" can help your potential customers better understand the features and benefits of your components.

About text formats

ACME AS123 LED Driver with Dimmer Control - Application Note

docman
Designer199081

docman

Member for

5 years 10 months

11

designs

1

groups

Add a bio to your profile to share information about yourself with other SystemVision users.

Description

The AS123 LED Driver from ACME Semiconductor (fictional) provides fully integrated PWM dimming and a programmable current set-point. This IC is specifically for automotive rear combination (tail/stop) lighting applications. It tightly regulates the desired string current under conditions of widely varying applied DC voltage.The PWM dimming function, which switches the LED on and off at just over 300 Hz, is active when the line input pin is high and the "PWM_disable" pin is low (The AS123 supports current programming using a single external resistor (see r_iset in the schematic). The resistor value can be selected to give the desired LED string current, using the following formula:r_iset = 1.85/i_desired The AS123 is capable of regulating up to 100mA per string continuously. Therefore the value of r_iset should be no less than 18.5 Ohms.In the simulation results, note that the brake/stop signal is active (12.6V) for the first 100ms, and then low (0 V) for the next 100ms. The tail light input is active the entire time, pulsing between 11.6V and 17.6V. Note that the LED current is approximately constant, at just under 30mA during the brake/stop on-time. When the brake/stop signal goes to 0V, then the LED current begins to PWM (55% duty-cycle, 325Hz).The user can move the waveform probes around, to look at other signals both on the schematic nets and within components. For example, move a probe onto one of the LED models and select to view the "power_dissipated".If the user creates a free account on systemvision, he can make a copy of this design. Then he can make changes to it, such as adjusting the r_iset resistor value. He can then simply re-run the simulation to see the effect of that change.See a "block diagram" schematic model of the ACME AS123 here: https://www.systemvision.com/design/acme-as123-led-driver-schematic-model-------------- End of Example Application Note ------------------If you are a component supplier, this type of "Executable Application Note" can help your potential customers better understand the features and benefits of your components.

About text formats

ACME LED Driver - full flat schematic

IvanGorobets
Designer188111

IvanGorobets

Member for

6 years 1 month

2

designs

1

groups

Add a bio to your profile to share information about yourself with other SystemVision users.

ACME AS123 LED Driver with Dimmer Control - Application Note

mamdhooh
Designer116146

mamdhooh

Member for

7 years 1 month

3

designs

1

groups

Add a bio to your profile to share information about yourself with other SystemVision users.

Description

The AS123 LED Driver from ACME Semiconductor (fictional) provides fully integrated PWM dimming and a programmable current set-point. This IC is specifically for automotive rear combination (tail/stop) lighting applications. It tightly regulates the desired string current under conditions of widely varying applied DC voltage.The PWM dimming function, which switches the LED on and off at just over 300 Hz, is active when the line input pin is high and the "PWM_disable" pin is low (The AS123 supports current programming using a single external resistor (see r_iset in the schematic). The resistor value can be selected to give the desired LED string current, using the following formula:r_iset = 1.85/i_desired The AS123 is capable of regulating up to 100mA per string continuously. Therefore the value of r_iset should be no less than 18.5 Ohms.In the simulation results, note that the brake/stop signal is active (12.6V) for the first 100ms, and then low (0 V) for the next 100ms. The tail light input is active the entire time, pulsing between 11.6V and 17.6V. Note that the LED current is approximately constant, at just under 30mA during the brake/stop on-time. When the brake/stop signal goes to 0V, then the LED current begins to PWM (55% duty-cycle, 325Hz).The user can move the waveform probes around, to look at other signals both on the schematic nets and within components. For example, move a probe onto one of the LED models and select to view the "power_dissipated" or the "lumens_output".If the user creates a free account on systemvision, he can make a copy of this design. Then he can make changes to it, such as adjusting the r_iset resistor value. He can then simply re-run the simulation to see the effect of that change.See a "block diagram" schematic model of the ACME AS123 here: https://www.systemvision.com/design/acme-as123-led-driver-schematic-model-------------- End of Example Application Note ------------------If you are a component supplier, this type of "Executable Application Note" can help your potential customers better understand the features and benefits of your components.

About text formats

Bobs_Private_Driver Circuit for 3 x 3 LED using ACME AS123

Bob Davis
Designer40261

Bob Davis

Member for

8 years

76

designs

1

groups

Add a bio to your profile to share information about yourself with other SystemVision users.

Terms of Use Cookie Notice Data Privacy Notice

MDonnellyDesigner112976

Member for

eusebiogermanDesigner230150

Member for

camilo06180401Designer229297

Member for

awcabDesigner135746

Member for

Chris MurrayDesigner9431

Member for

MurshidulHakimeeDesigner203528

Member for

docmanDesigner199081

Member for

IvanGorobetsDesigner188111

Member for

mamdhoohDesigner116146

Member for

Bob DavisDesigner40261

Member for

MDonnelly
Designer112976

eusebiogerman
Designer230150

camilo06180401
Designer229297

awcab
Designer135746

Chris Murray
Designer9431

MurshidulHakimee
Designer203528

docman
Designer199081

IvanGorobets
Designer188111

mamdhooh
Designer116146

Bob Davis
Designer40261