公开(公告)号：US10378946B2

公开(公告)日：2019-08-13

申请号：US15423260

申请日：2017-02-02

Applicant: HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.

Inventor： Ning Ge ,  Trudy Benjamin ,  Teck-Khim Neo ,  Joseph M. Torgerson ,  Neel Banerjee ,  George H. Corrigan, III

IPC: G01F23/26 ,  B41J2/175 ,  B41J2/14

Abstract: In some examples, a method of sensing an ink level includes applying a pre-charge voltage to a sense capacitor to charge the sense capacitor with a charge, sharing the charge between the sense capacitor and a reference capacitor, causing a reference voltage at a gate of an evaluation transistor, and determining a resistance from a drain to a source of the evaluation transistor that results from the reference voltage.

公开(公告)号：US20170146383A1

公开(公告)日：2017-05-25

申请号：US15423266

申请日：2017-02-02

Applicant: HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.

Inventor： Ning Ge ,  Trudy Benjamin ,  Teck-Khim Neo ,  Joseph M. Torgerson ,  Neel Banerjee ,  George H. Corrigan, III

IPC: G01F23/26 ,  B41J2/175

CPC classification number: B41J2/17566 ,  B41J2/14153 ,  B41J2/175 ,  B41J2002/17579 ,  G01F23/263

Abstract: In some examples, an ink level sensor includes a sense capacitor between a first node and ground, a first switch to couple a first voltage to the first node and charge the sense capacitor, a second switch to couple the first node with a second node and share the charge between the sense capacitor and a reference capacitor, causing a second voltage at the second node, and a transistor having a drain, a gate coupled to the second node, and a source coupled to ground, the transistor to provide a drain to source resistance in proportion to the second voltage.

公开(公告)号：US10082414B2

公开(公告)日：2018-09-25

申请号：US15423266

申请日：2017-02-02

Applicant: HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.

Inventor： Ning Ge ,  Trudy Benjamin ,  Teck-Khim Neo ,  Joseph M. Torgerson ,  Neel Banerjee ,  George H. Corrigan, III

IPC: G01F23/26 ,  B41J2/175 ,  B41J2/14

CPC classification number: G01F23/263 ,  B41J2/14153 ,  B41J2/175 ,  B41J2/17566 ,  B41J2002/17579

Abstract: In some examples, an ink level sensor includes a sense capacitor between a first node and ground, a first switch to couple a first voltage to the first node and charge the sense capacitor, a second switch to couple the first node with a second node and share the charge between the sense capacitor and a reference capacitor, causing a second voltage at the second node, and a transistor having a drain, a gate coupled to the second node, and a source coupled to ground, the transistor to provide a drain to source resistance in proportion to the second voltage.

公开(公告)号：US20170144451A1

公开(公告)日：2017-05-25

申请号：US15423260

申请日：2017-02-02

Applicant: HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.

Inventor： Ning Ge ,  Trudy Benjamin ,  Teck-Khim Neo ,  Joseph M. Torgerson ,  Neel Banerjee ,  George H. Corrigan, III

IPC: B41J2/175 ,  G01F23/26

CPC classification number: G01F23/263 ,  B41J2/14153 ,  B41J2/175 ,  B41J2/17566 ,  B41J2002/17579

Abstract: In some examples, a method of sensing an ink level includes applying a pre-charge voltage to a sense capacitor to charge the sense capacitor with a charge, sharing the charge between the sense capacitor and a reference capacitor, causing a reference voltage at a gate of an evaluation transistor, and determining a resistance from a drain to a source of the evaluation transistor that results from the reference voltage.