The new Lenovo laptop I bought comes with an AC to 20V DC external power converter. Why such a high DC voltage? I would expect that most of the circuitry in there operates on 5V or even 3.3V. While they may still need 12V to power disk drive motors or something, is there anything at all that operates on anything close to 20V?
Laptop power supply 20V
Started by ●November 24, 2012
Reply by ●November 24, 20122012-11-24
"David Harmon"> > The new Lenovo laptop I bought comes with an AC to 20V DC > external power converter. Why such a high DC voltage?** The PSU is also a battery charger and needs to have a voltage high enough to do that job. For a standard 14.8V Li-ion pack, the peak charging voltage is about 17V - so having 3V more available allows the regulator circuitry to work.> I would expect that most of the circuitry in there operates on 5V or even > 3.3V. While they may still need 12V to power disk drive motors > or something, is there anything at all that operates on anything > close to 20V?** The internal 14.8V battery. ... Phil
Reply by ●November 25, 20122012-11-25
On Fri, 23 Nov 2012 21:55:11 -0800, David Harmon <source@netcom.com> wrote:>The new Lenovo laptop I bought comes with an AC to 20V DC >external power converter. Why such a high DC voltage? I would >expect that most of the circuitry in there operates on 5V or even >3.3V. While they may still need 12V to power disk drive motors >or something, is there anything at all that operates on anything >close to 20V?The battery charger.
Reply by ●November 30, 20122012-11-30
David Harmon a expos� le 24/11/2012 :> The new Lenovo laptop I bought comes with an AC to 20V DC > external power converter. Why such a high DC voltage? I would > expect that most of the circuitry in there operates on 5V or even > 3.3V. While they may still need 12V to power disk drive motors > or something, is there anything at all that operates on anything > close to 20V?Hello, Furthermore I think the screen CFL through an inverter or the screen LEDs TBC With kind regards