supply voltage regulators 308 and 309 in the event of an overcurrent the power switch 306 can switch off the power to the power supply voltage regulators 308 and 309 when the power switch 306 is active thus sending 5v to the power supply voltage regulators 308 and 309 the power supply voltage regulators may convert 5v from the usb connection to the 3 3v needed to power the downstream elements regulators 308 and 309 may independently provide 3 3v to the digital components of the handheld device regulator 308 and the analog components of the handheld device regulator 309 the independence of the two regulators allows a highly uniform voltage source to be provided to the analog elements the microphone 314 speaker 315 and amplifiers 319 and 320 regardless of the power requirements of the digital components the eeprom 311 the audio codec 318 and the streaming controller 312 under the usb standard only 500 ma of current can be drawn from the usb connection preferably high power functions will draw less than 100 ma at power up thus the power switch 306 serves the additional function of shutting down the downstream devices if they attempt to draw more than this maximum amount of current note that the power to the usb hub controller chip is preferably.