Hi everybody,
I'm wondering if there are any "simple" solutions if the goal of a current sensing is just to know "some current flowing" or "no current flowing". My goal is to be able to detect whether a smartphone or tablet is actually loading or not: the primary is hence a USB cable carrying 5V (15V in some quick-charge setups), 0-3A DC, connected to a dedicated power supply. Several of these power supplies may be connected at once hence monitoring the AC before transformation won't give the desired information.
I'm aware of the following DC sensing techniques:
+ invasive: shunt resistors + op-amps
++ high-side (between Vcc and load)
++ low-side (between load and GND)
+ non-invasive / Hall effect: clamp-on current transformers or PCB-surface mounted
1. Are there any other techniques I missed? Perhaps some which are not widespread because they don't produce a linear output but would work for the desired boolean output ?
2. Clamp-on CTs have to be plugged on the 5/15V wire, not the entire (coated) USB cable, right? Expose a single wire in a standard USB cable sounds quite time-consuming... ok for a prototype, but not for more.
3. Supposing that CTs are not the right solution, do you see any risk using a invasive method or should I go for a PCB-mounted Hall effect sensor? I'd in both cases make a small PCB which has USB male on one side, female on the other and connects Vcc and GND + the sensor (I don't care about the data wires).
Thanks for reading
DonTseTse
I'm wondering if there are any "simple" solutions if the goal of a current sensing is just to know "some current flowing" or "no current flowing". My goal is to be able to detect whether a smartphone or tablet is actually loading or not: the primary is hence a USB cable carrying 5V (15V in some quick-charge setups), 0-3A DC, connected to a dedicated power supply. Several of these power supplies may be connected at once hence monitoring the AC before transformation won't give the desired information.
I'm aware of the following DC sensing techniques:
+ invasive: shunt resistors + op-amps
++ high-side (between Vcc and load)
++ low-side (between load and GND)
+ non-invasive / Hall effect: clamp-on current transformers or PCB-surface mounted
1. Are there any other techniques I missed? Perhaps some which are not widespread because they don't produce a linear output but would work for the desired boolean output ?
2. Clamp-on CTs have to be plugged on the 5/15V wire, not the entire (coated) USB cable, right? Expose a single wire in a standard USB cable sounds quite time-consuming... ok for a prototype, but not for more.
3. Supposing that CTs are not the right solution, do you see any risk using a invasive method or should I go for a PCB-mounted Hall effect sensor? I'd in both cases make a small PCB which has USB male on one side, female on the other and connects Vcc and GND + the sensor (I don't care about the data wires).
Thanks for reading
DonTseTse
