A safety switch for a lithium ion cell to prevent exceeding voltage limits associated with over-discharge and over-charging of a lithium ion cell. The safety switch includes at least one insulated gate transistor device having a low gate threshold voltage and a high transconductance to provide a power...http://www.google.es/patents/US5909103?utm_source=gb-gplus-sharePatente US5909103 - Safety switch for lithium ion battery
