Electric static discharge protection for power tools

Patent metadata

Field	Value
Publication number	US-10992207-B2
Application number	US-201916436138-A
Country	US
Kind code	B2
Filing date	Jun 10, 2019
Priority date	Jun 21, 2018
Publication date	Apr 27, 2021
Grant date	Apr 27, 2021

Abstract

A power tool has a housing, a motor disposed within the housing, a power supply circuit for providing power to the motor, a controller circuit for controlling the power provided to the motor, and an electric static discharge (ESD) protection circuit connected to the power supply circuit and the housing. The ESD protection circuit includes a first resistor connected to the power supply circuit and the housing. The first resistor may be a high impedance resistor. The ESD protection circuit may also have a first capacitor connected in parallel to the first resistor, a second resistor connected in series to the first resistor, and a second capacitor connected in series to the first capacitor and in parallel to the second resistor.

First claim

What is claimed is:

1. A power tool comprising:
a housing,
a motor disposed within the housing,
a power supply circuit for providing power to the motor,
a controller circuit for controlling the power provided to the motor, and
an electric static discharge (ESD) protection circuit connected to the power supply circuit and the housing, wherein the ESD protection circuit comprises:
a first resistor connected to the power supply circuit and the housing, the first resistor being a high impedance resistor;
a first capacitor connected in parallel to the first resistor;
a second resistor connected in series to the first resistor; and
a second capacitor connected in series to the first capacitor and in parallel to the second resistor.

2. The power tool of claim 1 , further comprising a third resistor connected in series to the first resistor and the power supply circuit.

3. The power tool of claim 2 , wherein the third resistor is a low impedance resistor.

4. A power tool comprising:
a housing,
a motor disposed within the housing,
a power supply circuit for providing power to the motor,
a controller circuit for controlling the power provided to the motor, and
an electric static discharge (ESD) protection circuit connected to the power supply circuit and the housing, wherein the ESD protection circuit comprises a first resistor connected to the power supply circuit and the housing, the first resistor being a low impedance resistor.

5. The power tool of claim 4 , further comprising a first capacitor connected in series to the first resistor.

6. The power tool of claim 5 , further comprising a second resistor connected in series to the first resistor, and in parallel to the first capacitor.

7. The power tool of claim 6 , wherein the second resistor is a high impedance resistor.

8. The power tool of claim 6 , further comprising a third resistor connected in series to the second resistor, and a second capacitor connected in series to the first capacitor and in parallel to the second resistor.

9. The power tool of claim 8 , wherein the third resistor is a high impedance resistor.

Assignees

• Black & Decker Inc

Inventors

• Eshleman Scott J
• Waikar Shailesh P
• Pai Ganapati K
• Narbut Joseph

Classifications

• H10W42/60

  protecting against electrostatic charges or discharges, e.g. Faraday shields (integrated devices comprising arrangements for electrical protection H10D89/60) · CPC title

• H02H9/041

  using a short-circuiting device · CPC title

• H05F3/02

  by means of earthing connections · CPC title

• B23D45/048

  the saw blade being adjustable according to angle of cut · CPC title

• H02K11/33

  Drive circuits, e.g. power electronics (H02K11/38 takes precedence) · CPC title