Circuit provides voltage regulation through a wide range of operating frequencies without intervals of high power dissipation

La Vigna, T.

English

NASA Technical Reports Server

Figure 1. Buck-Boost Voltage Regulator 
)roved regulator - the magnetic silicon controlled rectifiers. This imi 
should be of interest throughout the electronics 
industry. 
As illustrated in Figure 1, the regulator is 
composed of the following functional circuit elements: 
a master multivibrator (MN.), a magnetic amplifier, 
a slave M.V., a feedback controller, an inverter, 
a chopper, and an output filter. One output from 
the master M.V. is coupled through the variable-
phase delay magnetic amplifier to drive the slave 
M.V. Twin, phase-inverted square wave outputs are 
taken from the master, and similar outputs, delayed 
by a phaseshift 0, are taken from the slave. The 
master outputs are normally connected to the
amplifier. The regulator is described 
assuming this mode of operation. However, with equal 
facility, the connections of master and slave may be 
reversed, to operate the regulator in a phase-advanced 
mode and give maximum boost with maximum phase 
shift. 
The feedback controller compares a divided portion 
of the output voltage Eout with a zener reference 
voltage Eref, to produce an error signal, which is 
amplified and used to control the phase shift of 
the magnetic amplifier. 
The principle of operation of the regulator in-
volves combining a dc voltage source to be regulated 
with an ac voltage source in a chopper circuit. 
(continued overleaf) 
October 1970	 Brief 70-10005 
NASA TECH BRIEF 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage commercial 
application. Tech Briefs are available on a subscription basis from the National Technical Information Service, Springfield, 
Virginia 22151. Requests for individual copies or questions relating to the Tech Brief progam may be directed to the Tech-
nology Utilization Division, NASA, Code UT, Washington, D.C. 20546. 
Buck-Boost DC Voltage Regulator 
A circuit has been developed to provide buck-
boost voltage regulation through a wide range of 
operating frequencies without the intervals of high 
power dissipation which occur in similar circuits using 
Eb Dl 
p4 
E 6 	 Ti 
E.B S	 __ 
flJ U-1 D
bases of QI and Q2 and the slave outputs to the 
bases of Q3 and Q . The regulator operates in a 
phase-retarded mode, and gives maximum boost 
to the output voltage with minimum phase shift in 
Q3__ 
)	 JR 
CT1 
LS1	 CT1	 I	 Li 
J 
Eo.t 
1 
CTI-u
R3 R 
Master U Mag. J..Jsve I 
.-	
4 
M. V. I ( Amp.	 M. V. Q	 QC1 2 T	
111	 1 
ru Ui I Feedba] flJ Lii 
Eret	 Controller	 Eout 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Governmtht assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned.rights.
https://ntrs.nasa.gov/search.jsp?R=19700000005 2020-03-17T00:02:04+00:00Z
Q1 on 
J_L_n Master M.V. Drive 
I 
' Q 2 on 
	
Q4 on	 I 
*F- I 
	
I	 ii	 I 
	
I	 i I	 I	 Slave M.V. Drive 
Q3 on 
E in +EB	 I
Input to 03 
ET	 (03 conducts during_r
darkened portion 
LHP- 
of waveform) 
I	 ii 
	
En+EB	 I
Input to Q4 
Efl (04 conducts during 
darkened portion 
of waveform) 
Emn -EB	 I 
II 1 E in +EB 
Ein	
Eout 
Chopper output 
13 
L—L 	 L L Boost Mode 
I.	 E fl –E	 I 
I E in+ EB 
Ein	 n F_ Eout 
Chopper Output 
Neutral Mode 
E,– EB 
E1n+EB
Chopper Output 
Buck Mode 
..IIEII:If1EIIf'-E
Eout 
E in EB 
Figure 2. Ideal Waveforms 
Operation of the chopper circuit is adjustably phase 
displaced from that of the inverter to permit an 
additive or subtractive component of voltage to be 
impressed upon the dc input voltage as required 
for output voltage regulation. 
The inverter switching is controlled by the outputs 
of the master M.V. Conduction of either of the
inverter transistors Q  or Q2 allows the dc input, 
E 1 , to appear across the primary windings of auto-
transformer TI. This input voltage is coupled to the 
transformer secondary and provides an ac voltage, 
EB, which is combined with the input and then 
applied to the chopper circuit. The switching of 
the chopper circuit transistors, Q3 and Q, is con-
trolled by outputs from the slave M.V., and hence 
are phase delayed from the switching of the inverter 
transistors. This phase displacement, 3, is variable 
and results in the required switching of the power 
chopper transistors between conducting and noncon-
ducting states to cause the impressed voltage from 
the inverter to be either additive or subtractive. By 
varying the relative time duration of the buck (sub-
tractive) interval to the boost (additive) interval, 
the output level can be regulated. 
The subtractive mode of operation is achieved by 
maintaining one of the power chopper transistors Q 
and Q4 in conduction (by means of an inductive load 
Li and current transformer CT!) during the time 
when the subtractive half cycle of the impressed 
ac voltage is present at the active secondary winding 
of the autotransformer. 
The output from the chopper circuit is applied 
to an averaging filter Li-Cl, which smooths the 
pulsating dc to the desired output level. The result-
ant dc output, can thus be controlled at a value 
less than, equal to, or greater than E 1 . Figure 2 
is a graphic representation of the ideal waveforms of 
the circuit operating in either buck, boost, or neutral 
modes. 
Note: 
Requests for further information may be directed 
to:
Technology Utilization Officer 
Goddard Space Flight Center 
Greenbelt, Maryland 20771 
Reference: TSP70-10005 
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to: 
Patent Counsel 
Mail Code 204 
Goddard Space Flight Center 
Greenbelt, Maryland 20771
Source: T. LaVigna 
Goddard Space Flight Center

(GSC- 10735) 
Brief 70-1005	 Category 01


Buck-boost dc voltage regulator

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