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 Amendment on 03/31/2026.
Claim Objections
Claim 3 is objected to because of the following informalities: Claim 3, lines 14-15 recites “a voltage of the anode of the first diode”, which should be -- the voltage of the anode of the first diode -- because this term was previously presented in the claim.
Appropriate correction is required.
Claim Rejections - 35 USC § 102
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale or otherwise available to the public before the effective filing date of the claimed invention.
Claims 3 and 12 are rejected under 35 U.S.C. 102 (a)(1) as being anticipated by Person et al. (J. Person et al., “Short Circuit Detection Methods for Silicon Carbide (SiC) Power Semiconductors”, PCIM Europe, 2019, pp. 217-223.), hereinafter Person.
Regarding claim 3, Person discloses (see figures 1-8) a power conversion device (figure 6, part power conversion device that include a half bridge of SiC Mosfets) (figure 1) (Abstract; The use of Silicon Carbide (SiC) power semiconductors presents an attractive solution for increasing the efficiency and the power density of power converters) which has a semiconductor switching element (figure 1, part SiC Mosfet) having a first main electrode (figure 1, part SiC Mosfet; drain terminal), a second main electrode (figure 1, part SiC Mosfet; source terminal), and a gate (figure 1, part SiC Mosfet; gate terminal) and which controls a voltage of the gate (figure 1, part SiC Mosfet; voltage of the gate terminal) with the second main electrode as a reference (figure 1, part SiC Mosfet; source terminal as reference), to perform ON/OFF control (figure 1, part ON/OFF control through the voltage of the gate terminal at the SiC Mosfet) for current flowing between the first main electrode (figure 1, part SiC Mosfet; drain terminal) and the second main electrode (figure 1, part SiC Mosfet; source terminal) and perform power conversion between DC power and AC power (figure 6, part DC/AC conversion through the half bridge of SiC Mosfets at the power conversion device) (page 220; 3 Experimental validation of the desaturation detection; third paragraph; Fig. 6 is used with a half bridge module containing two 1200 V 72 A SiC MOSFET chips from ROHM), the power conversion device (figure 6, part power conversion device that include a half bridge of SiC Mosfets) (figure 1) comprising: a first diode (figure 1, part Dsc) having a cathode (figure 1, part Dsc; cathode) connected to the first main electrode (figure 1, part SiC Mosfet; drain terminal); a resistor (figure 1, part Rdesat,1) directly connecting an anode of the first diode (figure 1, part Dsc; anode) to the gate (figure 1, part gate terminal of the SiC Mosfet at left side of Rg,ext) such that the voltage of the anode of the first diode (figure 1, part voltage of the anode of Dsc) follows the gate voltage during turn-on (figure 1, part gate voltage of the SiC Mosfet during turn-on; through Rdesat,1); drive circuitry (figure 1, part driving circuitry generated by logic circuit and driver stage) which controls (figure 1, part through output of driver stage) the voltage of the gate of the semiconductor switching element (figure 1, part SiC Mosfet; voltage of the gate terminal); and short-circuit determination circuitry (figure 1, part short-circuit determination circuitry generated by the comparator) which determines whether or not short-circuit has occurred (figure 1, part through comparator) in the semiconductor switching element (figure 1, part SiC Mosfet), wherein the short-circuit determination circuitry (figure 1, part short-circuit determination circuitry generated by the comparator) determines, when a voltage of the anode of the first diode (figure 1, part voltage of the anode of Dsc; through Vdesat detection) is higher (figure 1, part through comparator) than a threshold voltage (figure 1, part Vdesat,th) (page 218; 2.1 Desaturation Detection Method; A frequently used method is the desaturation detection, which was initially proposed for IGBTs [7]. The Drain-Source voltage VDS is used as an indicator of a short circuit. A small current is generated in the detection circuit, which goes through the diode DSC and (additionally to ID) through the MOSFET. When VDS is not dropping to its saturation voltage during turn-on transient, a HSF is present and DSC blocks. In the case of a FUL the diode is initially conducting and after the fault VDS increases as a consequence of the rising drain current. When the voltage across DSC reaches its threshold value, it blocks the current. Consequently, the current is redirected and charges the capacitor. By sensing the voltage Vdesat inducted across the capacitor, a short circuit can be detected by a comparator) that is set to be higher than a mirror voltage, of the gate (figure 1, part mirror voltage of the gate), at which the semiconductor switching element starts to be in an ON state (figures 1 and 7, part SiC Mosfet; turning on) (page 220; 2.4 Comparison of short circuit detection methods for SiC MOSFET; third paragraph; the detection thresholds required for the detection circuit need to be determined beforehand in such a way that faulty detection is prevented during normal operation), that short-circuit has occurred in the semiconductor switching element (figure 1, part SiC Mosfet at short-circuit), and the drive circuitry sets (figure 1, part driving circuitry generated by logic circuit and driver stage), when the short-circuit determination circuitry determines that short-circuit has occurred (figure 1, part short-circuit determination circuitry generated by the comparator; when Vdesat is higher than Vdesat,th), the voltage of the gate (figure 1, part SiC Mosfet; voltage of the gate terminal) to a voltage for turning off the semiconductor switching element (figure 1, part SiC Mosfet; turning off) (page 220; 3 Experimental validation of the desaturation detection; second paragraph; The related circuit is shown in Fig. 1. If the drain-source voltage VDS (sensed by the SiC diode DSC) does not drop during normal turn on to it’s desaturation voltage VDS,sat after a specified blanking time, a comparator detects a fault. The logic circuit reacts and the SiC MOSFET is turned off by the gate driver).
Regarding claim 12, Person discloses everything claimed as applied above (see claim 3). Further, Person discloses (see figures 1-8) a material of the semiconductor switching element (figure 1, part SiC Mosfet) is a wide-bandgap semiconductor (Abstract; The use of Silicon Carbide (SiC) power semiconductors presents an attractive solution for increasing the efficiency and the power density of power converters).
Response to Arguments
Applicant's arguments filed 03/31/2026 have been fully considered but they are not persuasive.
Applicant’s argues on pages 9-10 of the Applicant's Response (“As amended, claim 1 requires a direct connection between the anode of the first diode and the gate of the semiconductor switching element via the resistor and fails to disclose "a resistor directly connecting an anode of the first diode to the gate," as recited in claim 3”).
The Examiner respectfully disagrees with Applicant’s arguments, because Person discloses a resistor (figure 1, part Rdesat,1) directly connecting an anode of the first diode (figure 1, part Dsc; anode) to the gate (figure 1, part gate terminal of the SiC Mosfet at left side of Rg,ext) such that the voltage of the anode of the first diode (figure 1, part voltage of the anode of Dsc) follows the gate voltage during turn-on (figure 1, part gate voltage of the SiC Mosfet during turn-on; through Rdesat,1). As discussed above, Person discloses the same connection of the resistor (figure 1, part Rdesat,1) between the anode of the first diode (figure 1, part Dsc; anode) and the gate (figure 1, part gate terminal of the SiC Mosfet at left side of Rg,ext). Therefore, Person meets with the claimed limitation. Furthermore, this configuration it is well know in the art and in order to provide more evidence about this statement is the reference Jimichi et al. (US 2019/0238050; Figure 3A/3B, parts 35, 37 and Q1/Q2).
Applicant’s argues on pages 10-11 of the Applicant's Response (“However, Person does not disclose or teach that the threshold voltage is specifically set to be higher than a mirror voltage of the gate at which the semiconductor switching element starts to be in an ON state, as now required by claim 3 as amended”).
The Examiner respectfully disagrees with Applicant’s arguments, because Person discloses a threshold voltage (figure 1, part Vdesat,th) that is set to be higher than a mirror voltage, of the gate (figure 1, part mirror voltage of the gate), at which the semiconductor switching element starts to be in an ON state (figures 1 and 7, part SiC Mosfet; turning on) (page 220; 2.4 Comparison of short circuit detection methods for SiC MOSFET; third paragraph; the detection thresholds required for the detection circuit need to be determined beforehand in such a way that faulty detection is prevented during normal operation). As discussed above, Person discloses the threshold voltage (figure 1, part Vdesat,th) that is set beforehand in such a way that faulty detection is prevented during normal operation and in order to meet with that it is clear that the threshold voltage (figure 1, part Vdesat,th) should be set to be higher than a mirror voltage, of the gate (figure 1, part mirror voltage of the gate), at which the semiconductor switching element starts to be in an ON state (figures 1 and 7, part SiC Mosfet; turning on) in order to prevent wrong fault detection when the semiconductor switching element starts to be in an ON state (figures 1 and 7, part SiC Mosfet; turning on). This statement happens because the contribution of the gate (figure 1, part gate terminal of the SiC Mosfet at left side of Rg,ext) connection to the detection (figure 1, part short-circuit determination circuitry generated by the comparator) through Rdesat,1 (figure 1, part Rdesat,1). Additional, it is obvious to one ordinary skill in the art to select or design this threshold voltage (based on this type of circuit) in this way higher than a mirror voltage of the gate at which the semiconductor switching element starts to be in an ON state in order to obtain more accurate protection that prevent wrong operation (when the gate voltage reach the mirror voltage) but at the same time protect the circuit with more accurate time.
Applicant’s argues on pages 11-12 of the Applicant's Response (“This claim amendment requires not only a structural connection between the anode of the first diode and the gate via the resistor, but also a specific functional relationship where the diode anode voltage tracks the gate voltage during turn-on operation”).
The Examiner respectfully disagrees with Applicant’s arguments, because (as discussed above) Person discloses a resistor (figure 1, part Rdesat,1) directly connecting an anode of the first diode (figure 1, part Dsc; anode) to the gate (figure 1, part gate terminal of the SiC Mosfet at left side of Rg,ext) such that the voltage of the anode of the first diode (figure 1, part voltage of the anode of Dsc) follows the gate voltage during turn-on (figure 1, part gate voltage of the SiC Mosfet during turn-on; through Rdesat,1). As discussed above, Person’s reference discloses all the same connection of the resistor (figure 1, part Rdesat,1) between the anode of the first diode (figure 1, part Dsc; anode) and the gate (figure 1, part gate terminal of the SiC Mosfet at left side of Rg,ext). Therefore, Person meets with the functional relationship where the voltage of the anode of the first diode (figure 1, part voltage of the anode of Dsc) follows the gate voltage during turn-on (figure 1, part gate voltage of the SiC Mosfet during turn-on; through Rdesat,1).
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any extension fee pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the date of this final action.
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
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