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Thermal and Voltage Compensation Circuit

IP.com Disclosure Number: IPCOM000047849D
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Daghir, KS: AUTHOR [+2]

Abstract

Disclosed is an improved thermal and voltage compensation circuit which generates an internal voltage that rises and falls with decreasing and increasing temperatures, respectively. Fig. 1A is a conventional thermal and voltage compensation circuit. Fig. 1B is an improved thermal and voltage compensation circuit. In addition to the good voltage regulation, the voltage at node C18 increases with temperature decrease and decreases with temperature increase. Examination of the sense amplifier of Fig. 2 shows that the voltage at node C18 should be at least two VBEs (approximately 1.6 volts) in order to achieve the proper Down level at V OUT. The switching window is determined by the voltage drop across resistor R8. The problem addressed is the wide variation in temperature and power supplies.

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Thermal and Voltage Compensation Circuit

Disclosed is an improved thermal and voltage compensation circuit which generates an internal voltage that rises and falls with decreasing and increasing temperatures, respectively. Fig. 1A is a conventional thermal and voltage compensation circuit. Fig. 1B is an improved thermal and voltage compensation circuit. In addition to the good voltage regulation, the voltage at node C18 increases with temperature decrease and decreases with temperature increase. Examination of the sense amplifier of Fig. 2 shows that the voltage at node C18 should be at least two VBEs (approximately 1.6 volts) in order to achieve the proper Down level at V OUT. The switching window is determined by the voltage drop across resistor R8. The problem addressed is the wide variation in temperature and power supplies. Thus, not only a well regulated voltage is required at node C18 but one that actually rises with decreasing temperature and falls with increasing temperature. This is because, as the temperature decreases, the switching window decreases. However, the VBEs of T21 and T22 increase for the same temperature change. Conversely, as the temperature increases, the switching window increases but the VBEs decrease. Referring to Fig. 1B, assuming the same current in T1 at the higher temperature, the base voltage of T2 decreases due to the higher voltage drop across RVH, because the resistance value of RVH increases with increasing temperature. The V...