devices common to the several figures are denoted by primed numbers . fig2 is a schematic diagram of an h - driver dc - to - dc converter 20 which uses an h - bridge , made up of transistors 15 - 18 , as a switching device . h - bridge drivers , as is well known to those skilled in the art , are very useful in high power consumption circuits . i . e ., motor drivers . h - bridge drivers are desirable for the low rdson ( resistance from source to drain with the channel biased on ) characteristics . having a low rdson enables the h - bridge driver &# 39 ; s transistors to be in series with a load for controlling and providing high currents thereto with minimal power loss . the transistors 15 - 18 , are typically vertical metal oxide semiconductor ( vmos ) or lateral drain metal oxide semiconductor ( ldmos ) transistors . an additional advantage of using vmos or ldmos transistors is that very little current is required at the gates to control large currents flowing from drain to source , hence circuit efficiency is high . referring again to fig2 the h - driver dc - to - dc converter 20 converts a dc voltage . v in having a magnitude , for example , equal to 20 volts , to an output voltage . v out having a magnitude , for example , equal to 5 volts . transistor 15 has a source connected to v in , a gate connected for receiving a switching signal s 1 and a drain connected to a node c . transistor 16 has a drain connected to the node c , a gate connected for receiving a switching signal s 2 and a source connected to a ground potential ( reference ). transistor 17 has a source connected to v in , a gate connected for receiving a switching signal s 3 and a drain connected to a node d . transistor 18 has a drain connected to the node d . a gate connected for receiving a switching signal s 4 and a source connected to ground potential . diodes 23 and 24 are body diodes of the transistors 16 and 18 , respectively . an inductor 21 is coupled between the node c and a node b . and an inductor 22 is coupled between the nodes b and d . a load , represented by a resistor 19 , is coupled between the node b and ground potential . v out is measured at the node b . in operation , the transistor 15 is biased on by the signal s 1 thereby allowing a current i 1 to flow through the inductor 21 to the load 19 . having a portion of the current i 1 stored in the inductor 21 , the transistor 15 is turned off and the transistor 16 is biased on by the signal s 2 for discharging the portion of the current i 1 to ground potential . before the inductor 21 is fully discharged , the transistor 17 is biased on by the signal s 3 causing a current i 2 to flow through the inductor 22 and into the load 19 . a portion of the current i 2 is stored in the inductor 22 and the transistor 17 is turned off . the transistor 18 is then biased on by the signal s 4 to discharge the portion of the current i 2 to ground potential . the magnitude of v out relative to the magnitude of v in can be controlled by controlling the duty cycle of the transistors 15 and 17 . referring now to fig3 the relative timing of the switching signals s 1 - s 4 is shown as well as the currents i 1 and i 2 . the signals s 1 and s 2 are 180 degrees out of phase while the signals s 3 and s 4 are 180 degrees out of phase . the currents i 1 and i 2 are sawtooth waveforms having their peaks 180 degrees out of phase . this assumes that a mutual inductance between the inductors 22 and 23 has a coupling coefficient substantially equal to zero . using two switching devices . i . e ., transistors 15 and 17 , to supply v out allows the effective switching speed to be doubled over that used in the sepic dc - to - dc converter 10 . increasing the switching speed acts to decrease the ripple in v out and hence reduces the need for output filtering . also , each inductor 22 and 23 need only carry half the current required of a single inductor and the current flowing in each switching transistor 15 and 17 is similarly reduced . fig4 depicts the voltage waveform of v out and the load current waveform of i 3 . the ripple present in v out is only 5 milli - volts ( from 5 . 037 volts to 5 . 032 volts ) which would require little or no filtering . the load current i 3 is shaped like a triangular wave having 115 milli - amps of ripple . very importantly , the conversion efficiency of the h - driver dc - to - dc converter 20 is substantially improved over that of the sepic dc - to - dc converter 10 since the load current i 3 is not required to flow through any power schottky diodes . instead , the load current is the sum of the currents i 1 and i 2 which flow through the transistors 15 and 17 , respectively . the low rdson associated with the transistors 15 and 17 allow for efficient conversion . the rdson of the transistors 15 and 17 may be further reduced , as is known by those skilled in the art , by using a charge pump circuit ( not shown ) to overdrive the switching signals s 1 and s 3 . further improvements in the output voltage may be realized by arranging the inductors 21 and 22 such that there is a mutual inductance therebetween . an h - driver dc - to - dc converter 30 incorporating such mutual inductance is shown in fig5 . the h - driver dc - to - dc converter 30 is connected identically as the h - driver dc - to - dc converter 20 with the exception that a magnetic core 26 is provided about which inductors 21 &# 39 ; and 22 &# 39 ; are wound . the timing of the signals s 1 - s 4 remains the same as that described with respect to fig3 . the mutual inductance of the inductors 21 &# 39 ; and 22 &# 39 ; has a coupling coefficient substantially equal to 0 . 88 in the preferred embodiment . the coupling co - efficient , however , is not critical and may be varied from approximately 0 . 7 to 0 . 9 with good results . however , a still lower coupling coefficient , for example , 0 . 5 , may provide suitable results . increasing the coupling coefficient too high , for example , to 0 . 99 , causes unacceptably large swings in the currents i &# 39 ; 1 and i &# 39 ; 2 . by incorporating mutual inductance into the h - driver dc - to - dc converter 30 , the currents i &# 39 ; 1 and i &# 39 ; 2 are transformed from sawtooth waveforms to trapezoidal waveforms as shown in fig6 . the trapezoidal waveforms provide an improved v out waveform , that is , there is less ripple . v out ripple in this instance , is reduced to only 3 milli - volts . the magnitudes of the current swings produced by the currents i &# 39 ; 1 and i &# 39 ; 2 are larger , approximately 1 . 3 amps in this case . this does not have an adverse impact on the operation of the h - driver dc - to - dc converter 30 since the output current is the sum of i &# 39 ; 1 and i &# 39 ; 2 . importantly , the inductors 21 &# 39 ; and 22 &# 39 ; are wound in the same direction . if the direction of one inductor is reversed ( so that the inductors 21 &# 39 ; and 22 &# 39 ; are wound in opposite directions ) the results are adversely affected in that the current i &# 39 ; 1 and i &# 39 ; 2 are no longer trapezoidal causing the output ripple to increase slightly . utilizing an h - bridge driver in a dc - to - dc converter substantially improves performance since power schottky diodes are eliminated and the switching frequency is increased . additionally , fewer and smaller storage components are required while the need to filter the output voltage is reduced . by utilizing the effects of mutual inductance between the inductors 21 &# 39 ; and 22 &# 39 ;, performance is improved still further by generating trapezoidal currents which further reduce output ripple . while the invention has been particularly described with reference to particular embodiments thereof , it will be understood by those skilled in the art that various other changes in detail may be made therein without departing from the spirit , scope , and teaching of the invention . for example only two switching elements have been shown , but it would be possible to use a greater number of such switching elements furthermore , switching devices other than field effect transistors could be incorporated . accordingly , the invention herein disclosed is to be limited only as specified in the following claims .