Configurable voltage mode controller is not available offtheshelf?

[cupoftea]

Hi,
The attached is a discrete voltage mode controller for a Boost converter.

The frequency, maximum duty cycle and overcurrent peak threshold are all easily changeable.
Why don’t such building blocks exist offtheshelf?

Applications such as multi chemistry battery chargers could really benefit from this.
(LTspice and pdf schem attached)

 

[Easy peasy]

Boost converter has no ability to limit peak current in event of heavy load on output ....

 

[cupoftea]

Thanks, are you referring to an mild overload condition?

Or are you referring to a heavy overload where the boost vout gets pulled below vin and the booster cant do anything to stop such an overcurrent?

The above voltage mode controller actually does have a peak current limit....but i admit its set to just above the level that is needed for max load.
However, the peak current threshold is also changeable.

 

[Easy peasy]

TL494 would meet most of your criteria I think ...

 

[FvM]

TL494 would meet most of your criteria I think ...

Except for by-pulse peak current limiting. Same applies to SG3524/3524A, another classical voltage mode controller.

 

[dick_freebird]

Well, when you want everything exactly your way you often end up alone.

 

[Easy peasy]

one of the op-amps in the TL494 can be used for instantaneous current limiting - it is fast enough ....

 

[BradtheRad]

Were boost control IC's attempted in the past? Could be a challenge. From what I've observed the boost converter has peculiarities which require attention to design and assembly. Example, inductors are prone to generate high voltage spikes, perhaps sparks.

One spark inside a lead-acid battery and you risk a battery explosion.

A feedback circuit must be installed and adjusted to operate properly. If load is absent, how shall a control IC respond? The boost converter gets no feedback until it causes at least a few current bursts from the inductor. If load is absent then output voltage may quickly reach damaging levels.

There's the reservoir capacitor's voltage rating. How does the IC know what it is?

And what if the reservoir capacitor is gone? The inductor is almost invincible as it must generate a burst of current burst. And the control IC might be all there is to absorb it.