DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
This office action is in response to the filling of the Request for Continued Examination (RCE) on 09/10/2026.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102 of this title, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 3 and 12 are rejected under 35 U.S.C. 103 as being unpatentable over Chen et al. (US 2024/0007095), hereinafter Chen, in view of Kaneda (US 2018/0331678).
Regarding claim 3, Chen discloses (see figures 1-7) a power conversion device (figure 1, part power conversion device where is apply the semiconductor switching element Mp) (paragraph [0003]; In recent years, the technology of silicon carbide power transistors has developed rapidly and is widely used in the fields of energy conversion and distribution, avionics and automobiles, renewable energy and electric traction, etc.) which has a semiconductor switching element (figure 1, part Mp) having a first main electrode (figure 1, part Mp; upper first main electrode), a second main electrode (figure 1, part Mp; lower second main electrode), and a gate (figure 1, part Mp; gate) and which controls a voltage of the gate (figure 1, part Vg) with the second main electrode as a reference (figure 1, part Mp; lower second main electrode as reference), to perform ON/OFF control (figure 1, part Mp; ON/OFF control) for current flowing between the first main electrode (figure 1, part Mp; upper first main electrode) and the second main electrode (figure 1, part Mp; lower second main electrode) and perform power conversion (figure 1, part power conversion device where is apply the semiconductor switching element Mp), the power conversion device (figures 1 and 2, part power conversion device where is apply the semiconductor switching element Mp) comprising: drive circuitry (figure 2, part drive circuitry generated by MPO/MP1, D1/D2, 242 and 230) which controls the voltage of the gate (figure 2, part Vg) of the semiconductor switching element (figure 2, part Mp); a first diode (figure 2, part SD1) having a cathode (figure 2, part SD1; cathode) connected to the first main electrode (figure 2, part Mp; upper first main electrode); a gate resistor (figure 2, part Rg1) connected between the drive circuitry (figure 2, part drive circuitry generated by MPO/MP1, D1/D2, 242 and 230; through D1) and the gate (figure 2, part Mp; gate); a resistor (figure 2, part Rd) directly connecting an anode of the first diode (figure 2, part SD1; anode) to a connection point between the gate resistor (figure 2, part Rg1) and the gate (figure 2, part Mp; gate) such that the voltage of the anode of the first diode (figure 2, part SD1; voltage of anode) follows the gate voltage during turn-on (figure 2, part Vg; during turn-on); and short-circuit determination circuitry (figure 2, part short-circuit determination circuitry generated by 241) which determines whether or not short-circuit has occurred (figure 2, part short-circuit determination circuitry generated by 241) in the semiconductor switching element (figure 2, part Mp) (paragraph [0024]; When the power transistor Mp is turned on and a short-circuit, the short-circuit current flows through the power transistor Mp… the voltage Va on its anode may be equal to the gate voltage Vg (e.g., equal to 20 volts). In addition, the voltage dividing circuit 210 may generate a dividing voltage Vb equal to, for example, volts. In this way, the comparator 241 compares the voltage Va with the dividing voltage Vb, and may generate the comparison result CP which is a logic high level. The logic circuit 242 may generate the control signal Ctrl which is a logic high level according to the driving signal DRV1 which is the same logic high level and the comparison result CP, and activate the pull-down circuit 230 to pull down the gate voltage Vg to the voltage V2. After the gate voltage Vg is pulled down, the power transistor Mp may be cut off to achieve the effect of short-circuit protection), wherein the short-circuit determination circuitry determines (figure 2, part short-circuit determination circuitry generated by 241), when the voltage figure 2, part Va) of the anode of the first diode (figure 2, part SD1; anode) is higher (figure 2, part through 241) than a threshold voltage (figure 2, part threshold voltage generated by Vb), that short-circuit has occurred (figure 2, part short-circuit determination circuitry generated by 241) in the semiconductor switching element (figure 2, part Mp) (paragraph [0024]), and the drive circuitry sets (figure 2, part drive circuitry generated by MPO/MP1, D1/D2, 242 and 230; through 230), when the short-circuit determination circuitry (figure 2, part short-circuit determination circuitry generated by 241) determines that short-circuit has occurred (figure 2, part short-circuit determination circuitry generated by 241; when Va is higher than Vb), the voltage of the gate (figure 2, part Vg) to a voltage for turning off (figure 2, part Vg for turning off) the semiconductor switching element (figure 2, part Mp) (paragraphs [0018]-[0025]; the power transistor Mp may be cut off to achieve the effect of short-circuit protection).
Chen does not expressly disclose perform power conversion between DC power and AC power; a threshold voltage that is set to be higher than a mirror voltage, of the gate, at which the semiconductor switching element starts to be in an ON state.
Kaneda teaches (see figures 1-6) perform power conversion between DC power and AC power (figure 1, part 1) (paragraph [0025]); a threshold voltage (figures 1 and 4, part Vref2) that is set to be higher than a mirror voltage (figures 1 and 4, part Vm), of the gate (figure 1, part G), at which the semiconductor switching element starts to be in an ON state (figure 1, part 11; starts to be in an ON state) (paragraph [0073]; The second reference voltage Vref2 may be higher than or equal to the mirror voltage).
It would have been obvious to one having ordinary skill in the art before the effective filling date of the claimed invention to configure the power conversion device of Chen with the power conversion device features as taught by Kaneda and obtain a power conversion device which has a semiconductor switching element having a first main electrode, a second main electrode, and a gate and which controls a voltage of the gate with the second main electrode as a reference, to perform ON/OFF control for current flowing between the first main electrode and the second main electrode and perform power conversion between DC power and AC power, the power conversion device comprising: drive circuitry which controls the voltage of the gate of the semiconductor switching element; a first diode having a cathode connected to the first main electrode; a gate resistor connected between the drive circuitry and the gate; a resistor directly connecting an anode of the first diode to a connection point between the gate resistor and the gate such that the voltage of the anode of the first diode follows the gate voltage during turn-on; and short-circuit determination circuitry which determines whether or not short-circuit has occurred in the semiconductor switching element, wherein the short-circuit determination circuitry determines, when the voltage of the anode of the first diode is higher than a threshold voltage that is set to be higher than a mirror voltage, of the gate, at which the semiconductor switching element starts to be in an ON state, that short-circuit has occurred in the semiconductor switching element, and the drive circuitry sets, when the short-circuit determination circuitry determines that short-circuit has occurred, the voltage of the gate to a voltage for turning off the semiconductor switching element, because it provides more efficient and reliable short circuit protection for DC/AC power conversion with more accurate and fast detection (paragraph [0006]).
Regarding claim 12, Chen and Kaneda teach everything claimed as applied above (see claim 3). Further, Chen discloses (see figures 1-7) a material of the semiconductor switching element (figures 1 and 2, part Mp) is a wide-bandgap semiconductor (Claim 19; power transistor is silicon carbide transistor).
Response to Arguments
Applicant’s arguments with respect to claim 3 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Carlos O. Rivera-Pérez, whose telephone number is (571) 272-2432 and fax is (571) 273-2432. The examiner can normally be reached on Monday through Friday, 8:30 AM – 5:00 PM EST.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Thienvu V. Tran can be reached on (571) 270-1276. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/C.O.R. /
Examiner, Art Unit 2838
/THIENVU V TRAN/ Supervisory Patent Examiner, Art Unit 2838
