Error-input power pin is not driven by output power pin

[Bastin]

i am trying to make a bipolar stepper motor board but this error is comming.i tried using net label and global label,but i cannot fix the problem

[paulvdh]

KiCad’s FAQ has quite a lot of detailed articles, including this one:

ErrType(3): Pin connected to some others pins but no pin to drive it

Additional reading about pin types in general: Electrical type of schematic symbol pins (KiCad 4 and KiCad 5) A good explanation about power symbols can be found in this stackexchange answer by @Seth_h KiCad does check if every component is connected to supply lines (*1) as a missing supply is a common mistake to make. Getting the error “ErrType(3): Pin connected to some others pins but no pin to drive it” means that KiCad thinks that some supply pin is not properly connected. Either because …

I see you already used a few PWR_FLAG symbols, even on the GND net. But you also need them on pins 1 and 15. the SENSE_A and SENSE_B are also defined as power inputs in KiCad’s default schematic symbol. I do agree this is a bit of a nuisance because these pins are usually connected with a shunt resistor… (Which you did draw on closer examination)

Some other advise:
Drawing boxes around circuit sections is becoming the latest fashion in the last few years, but it really does not help in any way. It does nothing that a bit of whitespace does not do equally well or better. Those boxes also cost time, both to draw, and to redraw when your circuit changes. They also make it more difficult to organize the schematic into logical blocks.

Adding titles to schematic sections is useful though. Those are usually the first thing to look at by someone unfamiliar with your schematic. I usually use a bigger font for them to put a bit more emphasis on them.

You are also using too many labels, and making the label text so small or overlapping with pin numbers makes it even harder to verify your schematic.

For organizing schematics, it also makes it clearer to follow generic rules, Signals from left to right, and voltages from top to bottom. You mostly did this, except for the power input connectors. I usually draw power inputs on the left, and connect them directly to voltage regulators (if present) and decoupling capacitors (fuses, EMI filters, etc). In a lot of cases following a wire is much easier and quicker then trying to find some label (especially when working from a screenshot, and you don’t have a search or highlight function available).

On top of that, L297 and L298 are really old IC’s. I guess they are some 30 to 40 years old now, and much better IC’s have been designed for stepper motors. L298 has low efficiency because it looses a few volts over the power switches (and that is why it needs a heatsink), and the mandatory extra power diodes on it’s output are also an added nuisance.

[ML9104]

@paulvdh

Drawing boxes around circuit sections is becoming the latest fashion in the last few years, but it really does not help in any way. It does nothing that a bit of whitespace does not do equally well or better.

Couldn’t have said it better myself. Silly fashion fad that reduces readability (but perhaps that’s the goal of the “Internet Gurus”?