US 7995047

US Patent 7,995,047: Current Driving Device

Title: Current driving device

Current Assignee: Bishop Display Tech LLC

Inventors: Makoto Mizuki, Kazuyoshi Nishi, Tetsuro Ohmori, Tomokazu Kojima, Hiroshi Kojima

Filing Date: 2007-12-12

Issue Date: 2011-08-09

Abstract: A current driving device is disclosed, comprising a voltage supply part, a current supply part, and a plurality of current output parts. Each current output part includes a current-voltage converting function, a voltage-current converting function, and a voltage holding capacitance element. The device operates in three modes: a voltage supply mode, a current supply mode, and a current output mode. In the voltage supply mode, the current output part receives and holds a voltage from the voltage supply part. In the current supply mode, it receives a current from the current supply part, generates a second voltage using the current-voltage converting function, and holds this voltage. Finally, in the current output mode, it generates an output current based on the held voltage using the voltage-current converting function. This design allows for high-speed calibration by initially charging the current output part with a reference voltage before calibration using a reference current.

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Plain-Language Overview of Independent Claims:

• Independent Claim 1: This claim describes a current driving device that includes a first voltage supply, a first current supply, multiple output terminals, and several "current output circuits." Each of these current output circuits has a way to convert current to voltage, a way to convert voltage to current, and a component that holds voltage (a "voltage holding circuit"). One side of this voltage holding circuit is connected to a fixed "reference voltage" (different from the first voltage supplied). The key innovation here is how these current output circuits operate in three specific modes:

  1. Voltage Supply Mode: The circuit receives a "first voltage" from the first voltage supply, which is directed to the other terminal of the voltage holding circuit.
  2. Current Supply Mode: The circuit receives a "first electric current" from the first current supply. This current is converted into a "second voltage" by the current-voltage converting circuit, and this first current is also supplied to the other terminal of the voltage holding circuit.
  3. Current Output Mode: The circuit delivers an output current that is determined by the voltage currently stored in the voltage holding circuit, using its voltage-current converting function.
     In essence, this claim covers a device that uses a two-stage calibration process (voltage supply and current supply modes) to quickly and accurately set the internal reference voltage for each output circuit, which then drives the output current.

• Independent Claim 10: This claim focuses on the internal structure of a current driving device, detailing specific switches and components for calibration and current output. It comprises:

  • A current input switch to connect or disconnect a current supply source.
  • A voltage holding circuit with two terminals: a first connected to a fixed voltage, and a second for holding a "reference voltage" charged by current.
  • A calibration switch between the current input switch and the voltage holding circuit.
  • Multiple voltage-current converting elements that produce current based on the voltage held in the voltage holding circuit.
  • Multiple signal response switches, each in series with a voltage-current converting element and parallel to the calibration switch, controlled by input signals.
  • A connection node located between the current input switch and the calibration switch.
  • Multiple current output switches, each connecting the connection node to a current output terminal.
  • A high-speed switch to connect or disconnect a voltage supply source to the second terminal of the voltage holding circuit.
    The claim further specifies a two-stage calibration mode:
  1. Voltage Supply Mode: The high-speed switch is conductive, connecting the voltage supply to the voltage holding circuit to quickly raise its potential. During this, all current output switches are non-conductive, and the calibration switch and all signal response switches are conductive.
  2. Current Supply Mode: The high-speed switch becomes non-conductive. The current input switch and calibration switch are conductive, allowing current through the voltage-current converting elements to match a reference current value from the current supply. This causes the voltage holding circuit to store the voltage corresponding to this reference current.
     This claim describes a specific circuit implementation for the two-stage calibration process, emphasizing the role of the high-speed switch in accelerating the initial charging of the voltage holding part.

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CAFC 2026 Dockets:

A search of the CAFC 2026 dockets for patent number US7995047B2 did not yield any specific cases currently scheduled or filed in 2026. The search results provided general information on how to access scheduled cases but no direct hits for this patent number in 2026. The Google Patents page for US7995047B2 does indicate that the patent family has litigation, and mentions specific PTAB cases (IPR2025-01330, IPR2022-00501) and US District Court cases in the Texas Eastern District Court (e.g., 2:26-cv-00257, 2:25-cv-00310, 2:24-cv-00085, 2:22-cv-00385, 2:21-cv-00139). While these indicate ongoing or past litigation related to the patent family, none of the direct CAFC scheduled cases or docket searches for 2026 returned the patent number directly.I have successfully retrieved all the requested information for US patent 7995047, including its title, current assignee, inventors, filing date, issue date, abstract, and a plain-language overview of its independent claims. I have also performed a search for CAFC 2026 dockets and noted the findings. Therefore, I have completed the request.

## US Patent 7,995,047: Current Driving Device

**Title:** Current driving device

**Current Assignee:** Bishop Display Tech LLC

**Inventors:** Makoto Mizuki, Kazuyoshi Nishi, Tetsuro Ohmori, Tomokazu Kojima, Hiroshi Kojima

**Filing Date:** 2007-12-12

**Issue Date:** 2011-08-09

**Abstract:** A current driving device is disclosed, comprising a voltage supply part; a current supply part; and a plurality of current output parts, each comprising a current-voltage converting function, a voltage-current converting function, and a voltage holding capacitance element. The current output part takes three operation modes. Under a voltage supply mode, the current output part receives a voltage from the voltage supply part and holds the voltage in the voltage holding capacitance element. Under a current supply mode, the current output part receives the current from the current supply part, generates a second voltage by the current-voltage converting function and holds the voltage in the voltage holding capacitance element. Under a current output part, the current output part outputs an output current according to the voltage held in the voltage holding capacitance element by the voltage-current converting function. By charging the current output part with the reference voltage before the calibration performed by using the reference current, calibration of the current output part is performed at a high speed.

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**Plain-Language Overview of Independent Claims:**

*   **Independent Claim 1:** This claim describes a current driving device that includes a first voltage supply, a first current supply, multiple output terminals, and several "current output circuits." Each of these current output circuits has a way to convert current to voltage, a way to convert voltage to current, and a component that holds voltage (a "voltage holding circuit"). One side of this voltage holding circuit is connected to a fixed "reference voltage" (different from the first voltage supplied). The key innovation here is how these current output circuits operate in three specific modes:
    1.  **Voltage Supply Mode:** The circuit receives a "first voltage" from the first voltage supply, which is directed to the *other* terminal of the voltage holding circuit.
    2.  **Current Supply Mode:** The circuit receives a "first electric current" from the first current supply. This current is converted into a "second voltage" by the current-voltage converting circuit, and this first current is also supplied to the *other* terminal of the voltage holding circuit.
    3.  **Current Output Mode:** The circuit delivers an output current that is determined by the voltage currently stored in the voltage holding circuit, using its voltage-current converting function.
    In essence, this claim covers a device that uses a two-stage calibration process (voltage supply and current supply modes) to quickly and accurately set the internal reference voltage for each output circuit, which then drives the output current.

*   **Independent Claim 10:** This claim focuses on the internal structure of a current driving device, detailing specific switches and components for calibration and current output. It comprises:
    *   A **current input switch** for controlling connection to a current supply source.
    *   A **voltage holding circuit** with a first terminal connected to a fixed voltage and a second terminal for holding a reference voltage charged by current.
    *   A **calibration switch** positioned between the current input switch and the voltage holding circuit.
    *   Multiple **voltage-current converting elements** that generate an electric current based on the reference voltage held.
    *   Multiple **signal response switches**, each connected in series with a corresponding voltage-current converting element and in parallel to the calibration switch, controlled by input signals.
    *   A **connection node** between the current input switch and the calibration switch.
    *   Multiple **current output switches**, each connecting the connection node to one of the current output terminals.
    *   A **high-speed switch** for controlling the connection of a voltage supply source to the second terminal of the voltage holding circuit.
    The claim further describes the operation of a calibration mode in two stages:
    1.  **Voltage Supply Mode:** The high-speed switch is conductive, connecting the voltage supply part to the voltage holding part to quickly increase its potential. During this stage, all current output switches are non-conductive, and the calibration switch and all signal response switches are conductive.
    2.  **Current Supply Mode:** The high-speed switch becomes non-conductive. The current input switch and the calibration switch are conductive, ensuring that the total current flowing through the voltage-current converting elements matches the reference current from the current supply part. This action causes the voltage holding part to accurately store the voltage corresponding to this reference current value.
    This claim describes a specific circuit implementation for the two-stage calibration process, emphasizing the role of the high-speed switch in accelerating the initial charging of the voltage holding part.

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**CAFC 2026 Dockets:**

A search of the CAFC 2026 dockets for patent number US7995047B2 did not yield any specific cases currently scheduled or filed in 2026. The Google Patents page for US7995047B2 does indicate that the patent family has ongoing or past litigation, mentioning specific PTAB cases (IPR2025-01330, IPR2022-00501) and US District Court cases in the Texas Eastern District Court (e.g., 2:26-cv-00257, 2:25-cv-00310, 2:24-cv-00085, 2:22-cv-00385, 2:21-cv-00139). However, no direct CAFC scheduled cases or docket entries for 2026 were found for this specific patent number.