A method to achieve a regulated analog transistor switch used in high-voltage applications up to an order of magnitude of 40 Volts protecting a load of excessive voltage and having a minimal drop voltage when battery voltage is not exceeding a threshold voltage critical to a load, comprising: providing a constant output voltage (Vh) not exceeding a maximum allowable voltage limit of a load, wherein the analog transistor switch is used in high-voltage applications up to an order of 40 Volts, wherein a supply voltage (Vup) could be much higher than this defined output voltage limit and wherein the ON-resistance of the transistor switch can be reduced to a minimum is comprising: protecting a load of excessive voltage in the high-voltage application by providing a supply voltage (Vsup) being higher than the maximum extended drain voltage of said transistor switch, further providing said transistor switch, a voltage divider (R5, R6) between said output voltage and ground, a differential amplifying means having its output (Vo) connected to the gate of said transistor switch, a reference voltage (Vref) being lower than said supply voltage (Vsup), and a resistive means connected between said supply voltage and the gate of said transistor switch, wherein said amplifying means comprises an operational amplifier (N4, N5, N6) and a two-stage amplifier (P1-P3,N1-N2),having Miller compensation, wherein the supply voltage has a voltage up to 40V wherein the operational amplifier (N4, N5, N6) is isolated from said supply voltage (Vsup) by high voltage transistors (HN1, HN2) biasing of said operational amplifier (N4, N5, N6) with said supply voltage, wherein said biasing is performed by the high voltage transistors (HV1, HV2) isolating said operational amplifier (N4,N5,N6,) from said supply voltage; amplifying the difference between the midpoint voltage (Vm) of said voltage divider (R5, R6) and said reference voltage (Vref) by said amplifying means and using the amplified difference to control the gate of said transistor switch,; minimizing the ON-resistance of said high voltage transistor by applying a constant maximum allowed gate-source voltage to said transistor switch in case said supply voltage is smaller or equal than said defined output voltage; and clipping of the output voltage (Vh) by adjusting said reference voltage and said voltage divider. protecting a load of excessive voltage in the high-voltage application by providing a supply voltage (Vsup) being higher than the maximum extended drain voltage of said transistor switch, further providing said transistor switch, a voltage divider (R5, R6) between said output voltage and ground, a differential amplifying means having its output (Vo) connected to the gate of said transistor switch, a reference voltage (Vref) being lower than said supply voltage (Vsup), and a resistive means connected between said supply voltage and the gate of said transistor switch, wherein said amplifying means comprises an operational amplifier (N4, N5, N6) and a two-stage amplifier (P1-P3,N1-N2),having Miller compensation, wherein the supply voltage has a voltage up to 40V wherein the operational amplifier (N4, N5, N6) is isolated from said supply voltage (Vsup) by high voltage transistors (HN1, HN2) biasing of said operational amplifier (N4, N5, N6) with said supply voltage, wherein said biasing is performed by the high voltage transistors (HV1, HV2) isolating said operational amplifier (N4,N5,N6,) from said supply voltage; amplifying the difference between the midpoint voltage (Vm) of said voltage divider (R5, R6) and said reference voltage (Vref) by said amplifying means and using the amplified difference to control the gate of said transistor switch,; minimizing the ON-resistance of said high voltage transistor by applying a constant maximum allowed gate-source voltage to said transistor switch in case said supply voltage is smaller or equal than said defined output voltage; and clipping of the output voltage (Vh) by adjusting said reference voltage and said voltage divider.