Single chip (IC) with adjustable constant current and PWM?

Hey,

I stumbled across the TLD5085EJ
in the LITIX series , it is a pretty awesome chip that offers to do it all up to 1800mA.

From the description:

• Wide Input Voltage Range from 4.75V to 45V
• Constant Current or Constant Voltage Regulation
• Drives LEDs in Buck Topology
• Very low shutdown current consumption (typ. 0.1µA)
• 370 kHz switching frequency
• PWM Dimming
• Integrated power-switch (output current up to 1.8A)
• Internal Soft-Start function
• ± 2% output current tolerance (± 4% for full load current range)
• Small thermally enhanced exposed heatslug package
• Over Temperature Shutdown


Sometimes a diagram says more then a 1000 words, so here is what I believe is a PWM controllable up-to 1.8A constant current circuit with that chip:



This chip uses about the same number of components as a LM317 just it offers Softstart, overtemp and what-not in the same.

Whoa? Bad part about it? Chip is discontinued from now in 2016. Still there is stock around. I will pick up some.

Infineon seem to have abandoned the integrated power control in favor of using MOSFETs outside.

The TLD5098 is today the head product I think. It has the advantage that it also can give analog dimming controlled via PWM also - However, it is getting a little too complicated for me to fully understand some of the concepts.

This is the first time I have seen full feature IC's in that power class. Is there other around?

Edited 1 time(s). Last edit at 07/15/2016 11:29AM by LarsK.

... be carefull, when drivin laser-diodes with it -- check for high current spikes when switching ON/OFF.

I had some drivers with constant current of up to 10Amps, but really short spikes (not detectable with normal multimeters or scopes) of some 30 to 50 Amps!

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

The whole point of soft start would be not to have that. It is the exact reason why I am not just making a simple voltage regulator circuit.

On the drivers that let you down, how fast were those transients?

Would I be able to see them?

My scope can do:

●ModelSO1062B
●Bandwidth:60MHz
●Channel:2
●Real-Sample Rate:1GSa/s
●Equivalent Sample Rate:25GSa/s
●Record Length:1M
●Rish time:≤1.7ns/≤3.5ns/≤5.8ns
●Timebase Accuracy:±50ppm
●Time Base Range:2ns/div-40s/div / 4ns/div-40s/div / 4ns/div-40s/div
●Input Impandance:1MΩ
●VOLTS/DIV Range:2mV/div～5V/div
●A/D Converter:8bit
●Position Range:±50V(5V/div), ±40V(2V/div～500mV/div), ±2V(200mV/div～50mV/div), ±400mV(20mV/div～2mV/div)
●DC Gain Accuracy:
±3% for Normal or Average acquisition mode, 5V/div to 10mV/div;
±4% for Normal or Average acquisition mode, 5mV/div to 2mV/div
●Bandwidth Limit:20MHz

Edited 1 time(s). Last edit at 07/15/2016 02:24PM by LarsK.

... I'm switching the currents with up to 2MHz bandwith and the spikes have some 10 nanoseconds duration.

The first image shows some 'typical' spikes and overshoots while switching OFF and ON - here is the current set to 3.6A and measured as voltage drop across the shunt resistor of 111 Milliohms - 0,4 V / 0,111 Ohm = 3,6 A:





And here current set to 10 Amps and the OFF-spike zoomed more in detail:



Edited 1 time(s). Last edit at 07/15/2016 05:17PM by VDX.

---

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]