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I'm building an automotive power distribution module which makes use of the Infineon BTS50010 high-side driver.

The high-side driver current is monitored via the sense pin (IS) connected to a microcontroller, see below schematic:

BTS50010 Application Schematic

If we say RLoad is a switching a load such as an ignition coil and as such, results in a varying HSD sense pin output, what would be a good way of accurately measuring load current?

The only way I can think of doing this would be by oversampling the current sense output with averaging in an attempt to calculate an accurate current value.

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  • \$\begingroup\$ See this for a very similar circuit. Basically just put a current sense resistor in series with the high side driver and measure across it in some convenient way. \$\endgroup\$
    – Lundin
    Commented Mar 18 at 13:42
  • \$\begingroup\$ @Lundin, I'm not sure how that would result in a different measurement than sampling the IS pin on the HSD? \$\endgroup\$
    – Joe
    Commented Mar 18 at 14:45
  • \$\begingroup\$ The main advantage is that you don't have to "marry" Infineon, so that you can replace the driver IC with something else. Infineon has a tradition of major logistics meltdowns every 5-10 years or so, when it becomes impossible to buy their products during an extended period of 1-2 years. Good products, horrible logistics - the company can't be trusted. \$\endgroup\$
    – Lundin
    Commented Mar 18 at 15:32

1 Answer 1

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The capacitor CSENSE in the schematic you posted acts as an analog averaging filter (RC low-pass). If you want to average the signal more, you can increase the value of this cap. No oversampling is needed.

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  • \$\begingroup\$ Thanks. Was overthinking this a bit. \$\endgroup\$
    – Joe
    Commented Mar 18 at 12:37
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    \$\begingroup\$ @Joe Overthinking is half of an engineer's job description. :) \$\endgroup\$
    – Jonathan S.
    Commented Mar 18 at 12:40

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