A switch-mode power converter including a bias circuit, comprising: a pair of input side power terminals configured to accept power from a power source (Vccp); a pair of output side power terminals configured to provide power to a load; a power converter power transformer comprising an E-shaped magnetic core having at least three magnetic paths, and power windings (N 1, N 2), wound around a path of the core; said power converter power transformer configured to provide a galvanic break to isolate said input side power terminals from said output side power terminals of said switch-mode power converter; a control circuit disposed on said output side of said switch-mode power converter; an initial bias primary winding (N p) wound on said E-shaped magnetic core; an initial bias secondary winding (N s) also wound on said E-shaped magnetic core, wherein said initial bias secondary winding (N s) shares at least one magnetic path in common with said initial bias primary winding (N p), and at least one of the paths shared in common by bias windings (N p and N s) does not include any of the power windings N 1, N 2 which are disposed on other paths; a driver coupled to said initial bias primary winding (N p), said driver powered by said power source, said driver configured to drive said initial bias primary winding with high frequency pulses when enabled by an enable signal; a rectifier coupled to said initial bias secondary winding to provide rectified pulses; and a capacitor coupled to said rectifier, said capacitor configured to smooth said rectified pulses, wherein said rectifier and said capacitor are configured to provide a voltage (Vccs) to power said control circuit during a power converter start-up, wherein, during start-up, said initial bias primary winding (Np) and said initial bias secondary winding (Ns) are configured to provide a source of electrical power for at least one circuit of said switch-mode power converter during operation of said power converter, and wherein after said start-up, i) said high frequency pulses are turned off, and said initial bias secondary winding (N p) is configured to provide electrical power to at least one circuit of said switch-mode power converter on said output side of said power converter; or ii) said initial bias primary winding is configured to provide electrical power to at least one circuit of said switch-mode power converter on said input side of said power converter, preferably wherein rectification is provided by a reverse protection diode of a transistor in said driver. a pair of input side power terminals configured to accept power from a power source (Vccp); a pair of output side power terminals configured to provide power to a load; a power converter power transformer comprising an E-shaped magnetic core having at least three magnetic paths, and power windings (N 1, N 2), wound around a path of the core; said power converter power transformer configured to provide a galvanic break to isolate said input side power terminals from said output side power terminals of said switch-mode power converter; a control circuit disposed on said output side of said switch-mode power converter; an initial bias primary winding (N p) wound on said E-shaped magnetic core; an initial bias secondary winding (N s) also wound on said E-shaped magnetic core, wherein said initial bias secondary winding (N s) shares at least one magnetic path in common with said initial bias primary winding (N p), and at least one of the paths shared in common by bias windings (N p and N s) does not include any of the power windings N 1, N 2 which are disposed on other paths; a driver coupled to said initial bias primary winding (N p), said driver powered by said power source, said driver configured to drive said initial bias primary winding with high frequency pulses when enabled by an enable signal; a rectifier coupled to said initial bias secondary winding to provide rectified pulses; and a capacitor coupled to said rectifier, said capacitor configured to smooth said rectified pulses, wherein said rectifier and said capacitor are configured to provide a voltage (Vccs) to power said control circuit during a power converter start-up, wherein, during start-up, said initial bias primary winding (Np) and said initial bias secondary winding (Ns) are configured to provide a source of electrical power for at least one circuit of said switch-mode power converter during operation of said power converter, and wherein after said start-up, i) said high frequency pulses are turned off, and said initial bias secondary winding (N p) is configured to provide electrical power to at least one circuit of said switch-mode power converter on said output side of said power converter; or ii) said initial bias primary winding is configured to provide electrical power to at least one circuit of said switch-mode power converter on said input side of said power converter, preferably wherein rectification is provided by a reverse protection diode of a transistor in said driver. i) said high frequency pulses are turned off, and said initial bias secondary winding (N p) is configured to provide electrical power to at least one circuit of said switch-mode power converter on said output side of said power converter; or ii) said initial bias primary winding is configured to provide electrical power to at least one circuit of said switch-mode power converter on said input side of said power converter, preferably wherein rectification is provided by a reverse protection diode of a transistor in said driver.