Sense (VSEN) terminal separation function
For a general voltage detector, the power supply of voltage monitoring terminal (sense terminal) is common to that of IC. A product that separates this voltage monitoring terminal (sense terminal) and power supply terminal is called sense (VSEN) terminal separation function or sense (VSEN) terminal separation product.
Separation of power supply terminal and voltage monitoring terminal (sense terminal) has a merit different from general voltage detector.
How to utilize the sense terminal separation function
1. The voltage of high-voltage line can be monitored with resistance divider
There are not so many voltage detectors that can directly monitor 12 V line or 24 V line.
When monitoring such high voltage, a method for indirectly monitoring the high voltage by monitoring the voltage dividing the resistance of high voltage is used.
In this method for monitoring voltage after dividing resistance, a general voltage detector whose monitoring terminal and power supply terminal are common causes fluctuation of power supply terminal voltage due to current consumption used for operation of IC, so malfunction may occur.
With a product for which sense terminal is separated, monitoring terminal and power supply terminal are separated. Thus, even if voltage dividing resistance is input to the monitoring terminal, IC does not malfunction and the high voltage can be safely monitored.
An example of monitoring of high-voltage line using a product for which sense terminal is separated is shown below.
In this example, the monitoring voltage of high voltage is divided by resistances R1 and R2 and input to the voltage monitoring terminal (VSEN terminal) of voltage detector. With this, high voltage is not applied to the voltage detector and general-purpose low-voltage voltage detector can be used.
Detect voltage = "detect voltage of voltage detector" x (R1 + R2) / R2
２．A detection signal can be kept even if the sense voltage is 0 V
With a general voltage detector whose monitoring terminal and power supply terminal are common, if the voltage of line to be monitored drops below the IC's operating voltage, the IC's internal circuit cannot normally operate. Thus, a correct detection signal cannot be output when the monitoring voltage is low.
With a product for which sense terminal is separated, if the operating voltage is supplied to the power supply terminal, correct detection signal can be output even if the voltage of sense terminal decreases to 0 V.