The method of setting up the over-current detection level of IC is indicated in six clause "standard application" of a data sheet. Over-current detection level is approximately calculated by the following equation. Io=Vref/Rs (A)Vref: reference voltage for current limiting, Rs: shunt resistance.However, since Rs is generally the value below and over 1ohm, it needs to be cautious of wiring resistance.Please confirm a setting check of an over-current detection level not with Vs power supply current but with motor winding current.
The current capability of output IGBT is the most important at a power supply sequence. As for IGBT, a fall of gate voltage (VCC voltage) reduces current capability. It becomes impossible to pass the current more than the saturation current of IGBT. In this state, it becomes generating loss of IGBT by multiplication output voltage and current, it becomes very big loss, and IGBT generates heat within an instant. Thereby, IGBT causes thermal destruction. Recommended sequences are the conditions that have IC used for the bottom of which situation satisfactory. However, when a recommended sequence cannot be satisfied, a point is extracted from the above-mentioned view and the validity of a sequence is taken into consideration. That is, it is "output current does not exceed the saturation current of IGBT in a power supply sequence. "For example, if power supply voltage falls, a current peak will fall under same PWM frequency. It will not become a problem if it can satisfy enough that peak current is below a saturation current of IGBT even if it has not satisfied the recommended power supply sequence here. In addition, about the saturation current of IGBT, please refer to the section "Current Derating for VCC" on data sheet.
The power supply up/down sequence of ECN30107, ECN30206, ECN30603, ECN30207, and ECN30604 is free. However, when the current limitation setting is assumed to be 1A or less, it becomes a power supply up/down sequence free in ECN30206 and ECN30603.
CB voltage is used for the internal power supply of IC. Especially, in LVSD (insufficient voltage detection) circuit, VCC is compared with CB voltage and LVSD operation level is decided. Here, when the external capacitor of CB is large, a problem is not in being static (at the time of regular operation), but in the transitional state when turning on a VCC power supply, it may become a problem. For example, when turning on a power supply, if an external capacitor is large, CB voltage rises behind time. By delay of CB voltage at this time, LVSD recovery voltage may fall from regulation voltage. This influence will be in the state of operating output IGBT on low gate voltage, and causes a fall of the output current capability of IGBT. Furthermore, when the current exceeding current capability tends to flow in this state, it may result in destruction of the IGBT. Enlarging CB capacitor capacity extremely cannot recommend you from the above thing. As a standard, we recommend 1 micro F or less. In addition, even if it is using the recommended power supply(VSP is low, sequence free), if VSP is turned on before the standup of CB voltage, it may be mentioned above. Therefore after stabilizing CB voltage, it recommends turning on VSP.
In ECN30204/30206/30207, it has reverse rotation detection terminal DM. Logic reversal of the DM terminal output logic is carried out at the time of an inversion. Furthermore, ECN3022 is equipped with the all-off function which all of output IGBTs turn off if VSP voltage is made below into 1.23V (typ.). It is used to turn off upper arm IGBT.
Please be equivalent to the internal clock frequency (refer to the section 6, "standard application" on data sheet) of IC, or set it as less than it. If input PWM frequency becomes remarkably high from a clock frequency, charge pump voltage (voltage between C+ and C-: VCP) may fall. In this case, please check charge pump voltage. Give more than 10V as a standard. The recommended setting frequency of internal clock frequency is 12-20kHz.
Please fix RS terminal to the ground potential of the logic system (15V) of IC.
Forward and reverse operation of a motor is possible for the product which attaches RWD terminal by controlling the apply voltage to RWD terminal. However, It is prohibition to perform reverse rotation during forward operation. This is because the following problems may occur, when RWD terminal is changed during motor rotation.
1) In an output inverter circuit, an arm short-circuit may occur at the moment of RWD change.
2) The large current generated at the time of a forward and reverse rotation change than a usual current limiting level may flow.
3) VS power supply voltage may leap up at the time of a forward to reverse change.
However, it is thought that forward and inversion operation is possible by taking the following measures.
No. 1) can avoid an arm short circuit by controlling VSP and RWD terminal by the following sequences.
"VSP OFF ->RWD change ->VSP ON"
However, in the timing of a change, a certain standby time of a fixed term is required in consideration of the delay time of the inverter output to an input.
No. 2) needs to take into consideration about the current accompanied by brake operation of the motor generated in inversion operation of a motor. At the time of forward and reverse rotation used as rapid brake operation, usually, it continues flowing free-wheeling current of upper arm until brake operation is completed unlike usual rotation operation. If a lower arm turns on by VSP ON at this time, the free-wheeling current ingredient of an upper arm will be added, and large current than usual will flow in an output inverter circuit. However, this free-wheeling current ingredient is undetectable with RS shunt resistance. Therefore large current than the current defined on the current limiting level will flow to an output inverter. If the rated current of an device is exceeded at this time, an inverter circuit may break.
While considering as "VSP OFF ->RWD change ->VSP ON" in performing right and reverse operation, it is necessary to set and change sufficient time at the time of change operation from the above point. Moreover, since VS power supply voltage may leap up at the time of an inversion, be fully careful not to exceed the maximum rating of a device.
Please connect MCR terminal to GND and fix the potential of an internal circuit. FG terminal is made into an open state.
The breakdown voltage of output devices has the specification for 305V / 1 minute supposing temporary incorrect connection. In ECN 3030/31, it is not this specification.
The setting method of a dead time is indicated for the application note of each form. Moreover, please set up a dead time about ECN3053/3054 in consideration of the turn-on delay time of IC, turn-off delay time, and the delay time of the power devices of operation to drive.
As for inverter IC series, the design for the application where extremely high reliability is required such as traffic equipment and so on is not performed. Therefore, the reliability of IC cannot be guaranteed when using it for the application such as traffic equipment etc.