8.Various methods of current sensing and advantage of current sensing resistors

8.1 Various methods of current sensing

１) Non-contact current sensing elements

・Hall element/sensor/IC
・Current transformer
・Combination of above two and others

Hall element/sensor

Current transformer

For large current

Advantages

・Sensing large current
・Small power loss
・Minimal influence to surrounding circuits

Disadvantages

・Expensive
・Larger than resistors
・Need space for it on board

２)　Contact current sensors

・Low resistance resistors（thin film, thick film, cement）　

Pulse shape of cement resistor

ESL affect
pulse shape

Pulse shape of KRL series

Rise and fall
are basically
intact

General purpose current sensing

Advantages

・Economical and precise
・Small size
・No special space needed
・Can be used for AD or DC

Disadvantages

a) Current loss, self heating
b) Equivalent series inductance (ESL) in high frequency
c) Solder cracks due to thermal coefficient of expansion mismatch

　　　Solution

a) Suppress heat with very low resistance
b) Low ESL structure
c) Use of anti-solder crack adhesive

KRL series

8.1 Various methods of current sensing

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