See section 6 of the "standard application" 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 1.0Ω, be careful to consider the resistance of wiring. Please conduct a check of the over-current detection level with the motor winding current not the Vs power supply current.
The current capability of output IGBTs is the most important for power supply sequencing. For the IGBT, a fall of gate voltage (VCC voltage) reduces the current capability. It becomes impossible to pass a current more than the saturation current of the IGBT. In this state, the generating loss of IGBT is a multiplication of output voltage and current, and can become very large, generates heat instantaneously. This can lead to thermal runaway and IGBT destruction. Recommended sequences are provided in application notes. Please also refer to the section "Current derating for VCC" on data sheet.
CB voltage is used for the internal power supply of the IC. In the LVSD low voltage detection circuit, VCC is compared to the CB voltage and LVSD operation level is decided. When the external capacitor of CB is large, a problem is unlikely during static period (at the time of regular operation) but during the transitional state when turning on a VCC power supply. For example, when turning on a power supply, if an external capacitor is large, CB voltage rises behind time. Due to the delay of CB, LVSD recovery voltage may fall below the regulated voltage level. This influence will be in the state of operating output IGBT at low gate voltage, causing a fall of the output current capability of IGBT. When the current capability is exceeded in this state, it may result in destruction of the IGBT. Too large a CB capacitor is not recommend. General recommendation is 1µF or less. Please allow the stabilisation of CB voltage before applying VSP signals.
ECN30206/30207 provides a reverse rotation detection terminal, DM. Logic reversal of the DM terminal output logic is carried out at the time of inversion. Furthermore, ECN3022 is equipped with an “all-off function” in which all the output IGBTs turn off where VSP voltage is set below 1.23V (typ.). This is used to turn off upper arm IGBTs.
Please consider the internal clock frequency (refer to the section 6, "standard application" on data sheet) and set it as less than that. If input PWM frequency is remarkably high compared to the clock frequency, the charge pump voltage (voltage between C+ and C-: VCP) may fall. In this case, please check charge pump voltage. Apply more than 10V as standard. The recommended setting frequency of the internal clock frequency is 12-20kHz.
Please fix the RS terminal to the ground potential of the logic system.
Forward and reverse operation of a motor is possible for the products with an RWD terminal, by controlling the applied voltage to RWD. It is prohibited to perform reverse rotation during forward operation. Problems may occur, when RWD terminal is changed during motor rotation. 1) In the 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, which is bigger than the typical current limiting level. 3) VS power supply voltage may jump upwards at the time of a forward to reverse change. Forward and inversion operation is possible by taking the following measures. a) Avoid an arm short circuit by controlling VSP and RWD terminal by the following sequences: "VSP OFF ->RWD change ->VSP ON“. A certain standby time with consideration of the delay time of the inverter output to an input should be adopted. b) Take into consideration the current accompanied with the braking of the motor. At the time of forward and reverse rotation used as rapid brake operation, a free-wheeling current may flow in the upper arm until the motor has stopped, unlike usual rotation operation. If a lower arm turns on with VSP ON during this time, the free-wheeling current of an upper arm will be added causing a large current to flow in the output inverter circuit. HowThis free-wheeling current is not detectable by the RS shunt resistance. When considering "VSP OFF ->RWD change ->VSP ON" whilst performing forward and reverse operation, it is necessary to set and allow sufficient time.
Connect the MCR terminal to GND and fix the potential of the internal circuit. FG terminal is set to an open state.
The breakdown voltage of output devices is 305V / 1 minute, assuming a temporary incorrect connection.
The setting method of dead time is indicated for the application note of each type name. Please set up the dead time for ECN3053/3054 considering the turn-on delay time of the IC, turn-off delay time and the delay time of the output MOS/IGBT of the drive.
Please consult with your local representative. In most cases, the inverter ICs are recommended for use in general domestic and industrial applications only.
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