Abstract:
An analgesic noise generator employs a transistor operated to provide a zener action that is broadcast as the active noise source in an integrated circuit amplifier packaged as a portable unit with means to control tone and volume and enhance life of the power source.

Description:
BACKGROUND 
     In todays active, mobilized society noise has become a common problem. No where is this felt more than when one is trying to fall asleep. In an effort to aid in sleeping the use of sleeping tablets has mushroomed. As is well known, however, this approach to the problem often creates physical and psychological side effects. 
     For this reason it was early on considered advantageous to induce sleep by physical methods. One such early method was to use electrodes to apply rectangular pulses. Another development was to create a hypnotic effect with lights, i.e., alternately dimming and brightening of a light source. Recently it has been recognized that white noise broadcast as a hum, for lack of a better worded description, can be quite effective as a sleep inducer. It is to the improvement of such an analgesic noise generator that this invention is directed. 
     SUMMARY 
     This invention provides a device, for assisting the induction of natural sleep, which is portable. 
     As stated above, this invention is concerned with the improvement of analgesic noise generating means. Specifically, the improvement is in using low current drain semiconductor means in a compact package so as to improve life of a power source for the device. 
     A more detailed object of the invention is to provide a transistorized zener means in combination with a circuit of enhancement type MOS transistors operated by a diode controlled multiple and single power source connection, said diode means preventing power source drain from one of the multiple batteries to the other. 
     Still another object of this invention is to provide a battery source for portable devices as above that will include a plurality of batteries connected by means to automatically select the highest charged of the batteries and protect the circuitry connected thereto. 
    
    
     DRAWING DESCRIPTION 
     FIG. 1 is an isometric view of the portable sleep inducer unit constructed according to this invention; 
     FIG. 2 is a plan view of the interior circuit arrangement within the housing of FIG. 1; 
     FIG. 3 is a circuit diagram of the analgesic noise circuit of FIG. 2; and 
     FIG. 4 is a circuit diagram of a portion of the circuit of FIG. 3 showing the internal structure of the IC chip thereof in more detail. 
    
    
     DETAILED DESCRIPTION 
     With more particular reference now to FIG. 1 there is shown a housing 20 having a base 22 and a cover 24. The cover 24 has formed on one side a pocket 26 for stowage of a speaker 28 and a speaker cord 30. The cover also has, projecting from a front face, tone control knob 32 and volume control 34. In the form shown the cover 24 is attached to base 22 by a flange 36. 
     As seen in FIG. 2, the base 22 has a plurality of spring clips 38 for mounting batteries 40 and 42. It should be noted that although two batteries are shown, there could be more used for additional fail-safe and lifetime provisioning as will appear hereinafter. The batteries shown are of the usual nine volt variety common to transistor radios with cap connectors 44 and 46 for leads 50, 52 and 54, 56. 
     Cover 24 has input connections 58, 60 and 62 to provide a common ground, as at 58 and separate positive inputs as at 60 and 62 to a printed circuit board 64 bonded to the cover 24 with its discrete components projecting therefrom for easy service without removal of the board 64 being necessary. 
     More particularly, there is mounted to the board 64 an PNP transistor 66, germanium diodes 68 and 70, capacitors 72, 73, 74, 75, 76, 77, 78, 80 and 82 and resistors 84, 86 and 88. The cover mounts switch 91 and pot 92 under the face for knobs 32 and 34. The structure is completed by an IC clip 96. 
     Diodes 68 and 70 in addition to preventing drain of any battery through another also act to preclude the connection in reverse of the batteries from affecting the circuitry powered by same. 
     The manner of connection of the batteries and the above discrete devices via a PC Board 64 is better shown by FIG. 3. As seen therein the IC chip, a Solitron CM 4007 as typical, is used having fourteen points of connections labeled as pins 1 through 14 whose input is pin 6 and whose output is pin 12. This is more particularly shown by FIG. 4 wherein the chip has three N-channel and three P-channel enhancement type MOS transistors between pins 6 and 12 connected in series by capacitors 78 and 82, each one of a set being connected via a minor feedback loop comprising resistors 89, 86 and 88 to bias the IC in a linear mode. In addition, a major feedback circuit comprised of resistor 84 and capacitor 80 is provided across the first two of the three to eliminate high frequency noise and allow more power in the audio range. 
     The circuit of FIG. 3 shows also the manner of connection of diodes 68 and 70 to positive outputs of batteries 40 and 42. The outputs of these diodes is joined at switch 98, a part, with pot 92, of the volume control under control of knob 34. Also, as seen by FIG. 3 knob 32 controls switching in capacitors 73, 75 and 77 in providing tone control to speaker jack 100. 
     OPERATION 
     In operation when switch 98 is turned on to permit current flows to pot 94 by being passed by one or both diodes 68 and 70, which is determined by the level of charge of batteries 40 and 42, i.e., if one is greater than the other than the diode of the other will be blocked from passing current as well as be prevented from shorting to the other, lower charge producing, battery. Pot 94 adjusts the current flow to PNP transistor 66 via resistor 90, whose emitter is grounded, to thereby adjustably control the reverse conduction of transistor 66 to establish a noise frequency therefrom by zener action thereof. Capacitor 72 by its cornering actions cuts off the frequency to that desired, whereas capacitor 74 feeds the frequency to the input pin 6 of the IC while blocking DC therefrom. 
     The IC by its nature is power conservative. However, in order to further conserve power to only that needed to produce a broadcast of the analgesic noise, the IC has the three minor feedback circuits to bias the IC in the linear mode to hold the output to approximately one-half voltage, and a major feedback circuit to optimize power in the audio range while eliminating the need for excess power by curtailing the high frequency range beyond that of the audio range. 
     A hum or waterfall sound is then broadcast via pin 12 to capacitor 73 to refine the tone which can be further refined by pot 92 switching in or out one or both of capacitors 75 and 77.