SERIES-SHUNT TYPE SEMICONDUCTOR CHOPPER

• US 3,603,814 A
• Filed: 03/27/1969
• Issued: 09/07/1971
• Est. Priority Date: 04/10/1968
• Status: Expired due to Term

• Current Assignee: Shin-Ichi Ohashi
• Original Assignee: Shin-Ichi Ohashi
• Inventors: Ohashi, Shin-ichi
• Primary Examiner(s): Heyman, John S.
• Application Number:
  US04/811,105
• Time in Patent Office: 894 Days
• Field of Search: 307/240,251,304,241,262
• US Class Current: 327/124
• CPC Class Codes: H03K 17/162 without feedback from the output circuit to the control circuit
• CPC Class Codes: H03K 17/6871 the output circuit comprising more than one controlled field-effect transistor

Abstract

A series-shunt type semiconductor chopper comprising two switching elements which are excited so as to be rendered conductive for a predetermined period of time when they have their conductivities changed, respectively.

Claims

2. A series-shunt type semiconductor chopper according to claim 1, wherein a capacitor is connected in parallel with an input thereto to thereby bypass spike noise tending to flow in the input.

3. A series-shunt type semiconductor chopper according to claim 1, wherein said excitation source comprises:

a switching voltage circuit having a pair of output terminals which produces at each of said output terminals a voltage which renders one of said field effect transistors, connected thereto alternately conductive and nonconductive, and wherein the transient portion of said voltage which renders said field effect transistor conductive has a shorter time constant relative to the portion of said voltage which renders said transistor nonconductive.

4. A series-shunt type semiconductor chopper according to claim 3, wherein said switching voltage circuit comprises a bistable multivibrator, the cyclic period of which is controlled by respective resistance and capacitance elements therein, said resistance and capacitance elements having preselected time constants to provide said predetermined period of time between the rendering of each of said field effect transistors conductive and nonconductive, each of said field effect transistors being voltage threshold sensitive, whereby there is a time delay between the instant each one of said switching elements previously in its nonconductive state switches into its conductive state by the application thereto of a first portion of said switching voltage which reaches the threshold during said relatively short transient portion and the instant when the other switching element previously in its conductive state switches into its nonconductive state by application thereto of a second portion of said switching voltage which reaches said threshold varying the relatively slower transient portion of said voltage.

5. A series-shunt type semiconductor chopper comprising:

a pair of input terminals and a pair of output terminals;

a first field effect transistor and a second field effect transistor, the first field effect transistor being connected in series with one of said input terminals and one of said output terminals, and the second of said field effect transistors being connected in parallel with said pair of output terminals;

an excitation source connected to each of said field effect transistors, for rendering each of said transistors alternately conductive and nonconductive respectively, including means for rendering each of said transistors conductive a predetermined period of time prior to rendering the other of said transistors nonconductive during the alternate excitation of said transistors, whereby switching spikes at the output of said chopper will be substantially eliminated.