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ACME AS123 LED Driver with Dimmer Control - Application Note

MihaiLuca
Designer93191

MihaiLuca

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7 years 4 months

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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.

Single-string Test - ACME AS123 LED Driver with Dimmer Control

Darrell
Designer10

Darrell

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10 years 5 months

624

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Big fan of VHDL-AMS

Fault Testing - ACME AS123 LED Driver with Dimmer Control

Mike Donnelly
Designer19

Mike Donnelly

Member for

10 years 5 months

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Member of the PartQuest Explore Development Team. Focused on modeling and simulation of analog, mixed-signal and multi-discipline systems covering a broad range of applications, including power electronics, controls and mechatronic systems.

ACME AS123 LED Driver with Dimmer Control - Application Note

Benigno
Designer72926

Benigno

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7 years 6 months

2

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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 select the “average” current "id_avg", which is a low-pass filtered view of the LED current.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.

Reference Design - ACME AS123 LED Driver with Dimmer Control

MarkWalter
Designer64546

MarkWalter

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7 years 8 months

2

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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 select the “average” current "id_avg", which is a low-pass filtered view of the LED current.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.

ACME AS123 LED Driver with Dimmer Control - Application Note

Mike Donnelly
Designer19

Mike Donnelly

Member for

10 years 5 months

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Member of the PartQuest Explore Development Team. Focused on modeling and simulation of analog, mixed-signal and multi-discipline systems covering a broad range of applications, including power electronics, controls and mechatronic systems.

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.

ACME AS123 LED Driver Schematic Model

Mike Donnelly
Designer19

Mike Donnelly

Member for

10 years 5 months

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Member of the PartQuest Explore Development Team. Focused on modeling and simulation of analog, mixed-signal and multi-discipline systems covering a broad range of applications, including power electronics, controls and mechatronic systems.

Description