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Old 04-07-2020, 03:21 PM   #50
Quoth
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Quote:
Originally Posted by patrickt View Post

Please explain why a phone, a laptop, and earphones can use USB C but an ereader couldn't.
Personally I won't buy ANYTHING that needs a USB-C power supply or has USB-C host outlets.
Engineering wise it's a spec ASKING for trouble. A device telling host what VOLTAGE to apply?
The standard solution is that apart from naked cell / battery chargers (Lead Acid Car battery, or Lithium pack with no internal charger) is that a connector from a host or a power supply ONLY supplies a fixed voltage.
The existing USB charge currents other than C are NOT decided by the host, they are only 5V (+/- 0.2V) and the slave gadget examines the D- or D+ pins to see if more than 100mA can drawn. If you only wire +V and 0V, you get 5V and the current supply is whatever the host can do and the slave may take only 100mA or 500mA max depending on era.

USB-C is stupid.
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