| 摘要 |
PROBLEM TO BE SOLVED: To allow performing a failure diagnosis of a device without requiring any oscilloscope or high speed ADC, by measuring pulse output of an acceleration voltage applied to a fetching electrode provided along an ion pool. SOLUTION: A monitor voltage Vd, which is provided by smoothing a pulse voltage Vh with a low-pass filter 27, is outputted to an ADC 28 and represented by Vd=α×Vh×[TON/(TON+TOFF)]. Where, Vh is a set voltage of high voltage power supply 11,αis resistive potential division ratio at resistors 23, 24, TON is a period when a pulse generator 17 and a MOSFET 14 are in the ON states, and TOFF is a period when the pulse generator 17 and the MOSFET 14 are in the OFF states. Based on this formula, the monitor voltage Vd is read while Vh and TON/TOFF ratio are varied differently, thereby a program 29 determines whether the monitor voltage Vd is a normal value, and therefore, the program 29 can perform failure diagnosis of a pulse voltage generating circuit. |
